Denial of Service
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
How It Works
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions. Attackers exploit asymmetry: minimal attacker effort produces disproportionate resource consumption on the target. Application-level attacks use specially crafted inputs that trigger expensive operations—a regex engine processing malicious patterns can backtrack exponentially, or XML parsers recursively expand entities until memory exhausts. Network-level attacks flood targets with connection requests or amplify traffic through reflection, but application vulnerabilities often provide the most efficient attack surface.
The attack typically begins with reconnaissance to identify resource-intensive operations or unprotected endpoints. For algorithmic complexity attacks, adversaries craft inputs hitting worst-case performance—hash collision inputs filling hash tables with collisions, deeply nested JSON triggering recursive parsing, or pathological regex patterns like (a+)+b against strings of repeated 'a' characters. Resource exhaustion attacks open thousands of connections, upload massive files to unbounded storage, or trigger memory leaks through repeated operations. Crash-based attacks target error handling gaps: null pointer dereferences, unhandled exceptions in parsers, or assertion failures that terminate processes.
Impact
- Service unavailability preventing legitimate users from accessing applications during attack duration
- Revenue loss from downtime in e-commerce, SaaS platforms, or transaction processing systems
- Cascading failures as resource exhaustion spreads to dependent services or database connections pool out
- SLA violations triggering financial penalties and damaging customer trust
- Security team distraction providing cover for data exfiltration or intrusion attempts running concurrently
Real-World Examples
CVE-2018-1000544 in Ruby's WEBrick server allowed ReDoS through malicious HTTP headers containing specially crafted patterns that caused the regex engine to backtrack exponentially, freezing request processing threads. A single attacker could saturate all available workers.
Cloudflare experienced a global outage in 2019 when a single WAF rule containing an unoptimized regex hit pathological cases on legitimate traffic spikes. The .*(?:.*=.*)* pattern exhibited catastrophic backtracking, consuming CPU cycles across their edge network until the rule was disabled.
CVE-2013-1664 demonstrated XML bomb vulnerabilities in Python's XML libraries. Attackers uploaded XML documents with nested entity definitions-each entity expanding to ten copies of the previous level. A 1KB upload could expand to gigabytes in memory during parsing, crashing applications instantly.
Mitigation
- Strict input validation enforcing size limits, complexity bounds, and nesting depth restrictions before processing
- Request rate limiting per IP address, API key, or user session with exponential backoff
- Timeout enforcement terminating operations exceeding reasonable execution windows (typically 1-5 seconds)
- Resource quotas limiting memory allocation, CPU time, and connection counts per request or tenant
- Regex complexity analysis using linear-time algorithms or sanitizing patterns to eliminate backtracking
- Circuit breakers automatically rejecting requests when error rates or latency thresholds indicate degradation
- Load balancing and autoscaling distributing traffic across instances with automatic capacity expansion
Recent CVEs (40180)
Use after free in Media Stream in Google Chrome prior to 120.0.6099.62 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Dell PowerEdge platforms 16G Intel E5 BIOS and Dell Precision BIOS, version 1.4.4, contain active debug code security vulnerability. Rated medium severity (CVSS 6.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
Dell PowerEdge platforms 16G Intel E5 BIOS and Dell Precision BIOS, version 1.4.4, contain active debug code security vulnerability. Rated medium severity (CVSS 6.8), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
The tokio-boring library in version 4.0.0 is affected by a memory leak issue that can lead to excessive resource consumption and potential DoS by resource exhaustion. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Dell PowerScale OneFS, 8.2.2.x through 9.6.0.x, contains an improper control of a resource through its lifetime vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Dell OS10 Networking Switches running 10.5.2.x and above contain an Uncontrolled Resource Consumption (Denial of Service) vulnerability, when switches are configured with VLT and VRRP. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Transient DOS when processing a NULL buffer while parsing WLAN vdev. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Memory corruption when processing cmd parameters while parsing vdev. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Under certain scenarios the WLAN Firmware will reach an assertion due to state confusion while looking up peer ids. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Azure RTOS USBX is a USB host, device, and on-the-go (OTG) embedded stack, that is fully integrated with Azure RTOS ThreadX. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
lestrrat-go/jwx is a Go module implementing various JWx (JWA/JWE/JWK/JWS/JWT, otherwise known as JOSE) technologies. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
fish is a smart and user-friendly command line shell for macOS, Linux, and the rest of the family. Rated medium severity (CVSS 6.6), this vulnerability is low attack complexity. Public exploit code available.
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Several versions of ALEOS, including ALEOS 4.16.0, include an opensource third-party component which can be exploited from the local area network, resulting in a Denial of Service condition for the. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
The ACEManager component of ALEOS 4.16 and earlier does not perform input sanitization during authentication, which could potentially result in a Denial of Service (DoS) condition for ACEManager. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
The ACEManager component of ALEOS 4.16 and earlier does not adequately perform input sanitization during authentication, which could potentially result in a Denial of Service (DoS) condition for. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In callback_thread_event of com_android_bluetooth_btservice_AdapterService.cpp, there is a possible memory corruption due to a use after free. Rated high severity (CVSS 8.8), this vulnerability is no authentication required, low attack complexity.
In run of MDnsSdListener.cpp, there is a possible memory corruption due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.
In forceReplaceShortcutInner of ShortcutPackage.java, there is a possible way to register unlimited packages due to a missing bounds check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
In saveToXml of PersistableBundle.java, invalid data could lead to local persistent denial of service with no additional execution privileges needed. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
In PMRChangeSparseMemOSMem of physmem_osmem_linux.c, there is a possible arbitrary code execution due to a use after free. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In RGXBackingZSBuffer of rgxta3d.c, there is a possible arbitrary code execution due to a use after free. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In DevmemIntMapPMR of devicemem_server.c, there is a possible arbitrary code execution due to a use after free. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In PMR_ReadBytes of pmr.c, there is a possible arbitrary code execution due to a use after free. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In RGXUnbackingZSBuffer of rgxta3d.c, there is a possible arbitrary code execution due to a use after free. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Traefik is an open source HTTP reverse proxy and load balancer. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In 5G Modem, there is a possible system crash due to improper error handling. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM DB2 for Linux, UNIX and Windows (includes Db2 Connect Server) 10.5, 11.1, and 11.5 is vulnerable to denial of service with a specially crafted RUNSTATS command on an 8TB table. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 10.5, 11.1, and 11.5 is vulnerable to denial of service with a specially crafted SQL statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 11.1, and 11.5 is vulnerable to a denial of service through a specially crafted federated query on specific federation objects. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 10.5, 11.1, and 11.5 is vulnerable to denial of service with a specially crafted query. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 11.5 federated server is vulnerable to a denial of service when a specially crafted cursor is used. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In gnss service, there is a possible out of bounds write due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In telecom service, there is a possible missing permission check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In sysui, there is a possible missing permission check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In Gnss service, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In ril service, there is a possible out of bounds write due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In phasecheckserver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In gpu driver, there is a possible out of bounds write due to a incorrect bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In TeleService, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gpu driver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gpu driver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In camera service, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In camera service, there is a possible use after free due to a logic error. Rated medium severity (CVSS 6.7), this vulnerability is low attack complexity. No vendor patch available.
In flv extractor, there is a possible missing verification incorrect input. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In video service, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In video service, there is a possible out of bounds read due to a incorrect bounds check. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
In gsp driver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gsp driver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gsp driver, there is a possible out of bounds write due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gpu driver, there is a possible out of bounds read due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In gpu driver, there is a possible out of bounds write due to a missing bounds check. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
IBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 10.5, 11.1, 11.5 is vulnerable to denial of service under extreme stress conditions. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
IBM Db2 for Linux, UNIX and Windows (includes DB2 Connect Server) 11.5 CLI is vulnerable to a denial of service when a specially crafted request is used. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
InteraXon Muse 2 devices allow remote attackers to cause a denial of service (incorrect Muse App report of an outstanding, calm meditation state) via a 480 MHz RF carrier that is modulated by a. Rated medium severity (CVSS 6.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
IBM InfoSphere Information Server 11.7 could allow a remote attacker to cause a denial of service due to improper input validation. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required.
IBM InfoSphere Information Server 11.7 could allow a remote attacker to cause a denial of service due to improper input validation. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Use After Free vulnerability in Arm Ltd Bifrost GPU Kernel Driver, Arm Ltd Valhall GPU Kernel Driver, Arm Ltd Arm 5th Gen GPU Architecture Kernel Driver allows a local non-privileged user to make. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
A vulnerability of Uncontrolled Resource Consumption has been identified in STARDOM provided by Yokogawa Electric Corporation. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An issue has been discovered in GitLab EE affecting all versions starting from 10.5 before 16.4.3, all versions starting from 16.5 before 16.5.3, all versions starting from 16.6 before 16.6.1. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Buffer Overflow vulnerability in /apply.cgi in Shenzhen Libituo Technology Co., Ltd LBT-T300-T310 v2.2.2.6 allows attackers to cause a denial of service via the ApCliAuthMode parameter. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An input validation vulnerability in the Schweitzer Engineering Laboratories SEL-451 could allow a remote authenticated attacker to create a denial of service against the system and locking out. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An allocation of resources without limits or throttling vulnerability in the Schweitzer Engineering Laboratories SEL-451 could allow a remote authenticated attacker to make the system unavailable for. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in Sierra Wireless, Inc ALEOS could potentially allow a remote attacker to trigger a Denial of Service (DoS) condition for. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An issue in the box_deserialize_reusing function in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the box_equal function in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the box_col_len function in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the box_add function in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the box_div function in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the cha_cmp function of openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
An issue in the box_mpy function of openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) after running a SELECT statement. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
A stack overflow in openlink virtuoso-opensource v7.2.11 allows attackers to cause a Denial of Service (DoS) via crafted SQL statements. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
Use after free in libavif in Google Chrome prior to 119.0.6045.199 allowed a remote attacker to potentially exploit heap corruption via a crafted avif file. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in libavif in Google Chrome prior to 119.0.6045.199 allowed a remote attacker to potentially exploit heap corruption via a crafted avif file. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in Mojo in Google Chrome prior to 119.0.6045.199 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in WebAudio in Google Chrome prior to 119.0.6045.199 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An authenticated malicious user could initiate multiple concurrent requests, each requesting multiple dashboard exports, leading to a possible denial of service.0.0. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Knative Serving builds on Kubernetes to support deploying and serving of applications and functions as serverless containers. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
A use-after-free vulnerability in BusyBox v.1.36.1 allows attackers to cause a denial of service via a crafted awk pattern in the awk.c evaluate function. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
The 10Web Booster WordPress plugin before 2.24.18 does not validate the option name given to some AJAX actions, allowing unauthenticated users to delete arbitrary options from the database, leading. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
A flaw was found in libnbd, due to a malicious Network Block Device (NBD), a protocol for accessing Block Devices such as hard disks over a Network. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Mattermost fails to limit the log size of server logs allowing an attacker sending specially crafted requests to different endpoints to potentially overflow the log. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.