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 (40166)
NVIDIA GPU Driver for Windows and Linux contains a vulnerability where an improper check or improper handling of exception conditions might lead to denial of service. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
NVIDIA GPU Display Driver for Windows and Linux contains a vulnerability where a user can cause an untrusted pointer dereference by executing a driver API. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
NVIDIA GPU driver for Windows and Linux contains a vulnerability where a user can cause an out-of-bounds write. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
NVIDIA vGPU software for Linux contains a vulnerability where the software can dereference a NULL pointer. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
NVIDIA vGPU software for Windows and Linux contains a vulnerability where unprivileged users could execute privileged operations on the host. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
NVIDIA vGPU software for Linux contains a vulnerability in the Virtual GPU Manager, where the guest OS could execute privileged operations. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
In gpu_slc_get_region of pixel_gpu_slc.c, there is a possible EoP due to a use after free. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.
In DeregAcceptProcINT of cn_NrmmStateDeregInit.cpp, there is a possible denial of service due to a logic error in the code. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
there is a possible cellular denial of service due to a logic error in the code. Rated medium severity (CVSS 4.0), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
there is a possible persistent Denial of Service due to test/debugging code left in a production build. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. No vendor patch available.
Remote prevention of access to cellular service with no user interaction (for example, crashing the cellular radio service with a malformed packet). Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
In lwis_fence_signal of lwis_debug.c, there is a possible Use after Free due to improper locking. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
In lwis_process_transactions_in_queue of lwis_transaction.c, there is a possible use after free due to a use after free. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.
Deep Sea Electronics DSE855 Multipart Boundary Infinite Loop Denial-of-Service Vulnerability. Rated medium severity (CVSS 6.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
A flaw was discovered in Elasticsearch, affecting document ingestion when an index template contains a dynamic field mapping of “passthrough” type. Rated medium severity (CVSS 4.9), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
CrateDB is a distributed SQL database. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
Audition versions 24.2, 23.6.4 and earlier are affected by a NULL Pointer Dereference vulnerability that could result in an application denial-of-service condition. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
An issue has been discovered in GitLab CE/EE affecting all versions starting from 8.4 prior to 16.10.7, starting from 16.11 prior to 16.11.4, and starting from 17.0 prior to 17.0.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An issue has been discovered in GitLab CE/EE affecting all versions prior to 16.10.7, starting from 16.11 prior to 16.11.4, and starting from 17.0 prior to 17.0.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
An issue has been discovered in GitLab CE/EE affecting all versions starting from 13.1 prior to 16.10.7, starting from 16.11 prior to 16.11.4, and starting from 17.0 prior to 17.0.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, 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 a denial of service as the server may crash when using a specially crafted query on certain. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
cause denial of service, device reboot, or an attacker gaining full control of the relay when a specially crafted reset token is entered into the front panel of the device. Rated medium severity (CVSS 6.8), this vulnerability is 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 under certain conditions. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
device’s web interface when an attacker sends a specially crafted HTTP request. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Out-of-bounds Read vulnerability could allow attackers to read data from memory outside the intended buffer boundaries.
device when an attacker sends a specially crafted HTTP request. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
interface over the product network interface. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A path traversal vulnerability in mintplex-labs/anything-llm allowed a manager to bypass the `normalizePath()` function, intended to defend against path traversal attacks. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.
The WordPress Header Builder Plugin - Pearl plugin for WordPress is vulnerable to unauthorized site option deletion due to a missing validation and capability checks on the stm_hb_delete() function. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Dell Client BIOS contains an Out-of-bounds Write vulnerability. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
RMQTT Broker 0.4.0 is vulnerable to Denial of Service (DoS) due to improper session resource management. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Use after free in PDFium in Google Chrome prior to 126.0.6478.54 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF 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 Audio in Google Chrome prior to 126.0.6478.54 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF 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 Browser UI in Google Chrome prior to 126.0.6478.54 allowed a remote attacker who convinced a user to engage in specific UI gestures to perform an out of bounds memory read via a. 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 V8 in Google Chrome prior to 126.0.6478.54 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 Dawn in Google Chrome prior to 126.0.6478.54 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 Dawn in Google Chrome prior to 126.0.6478.54 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.
Improper exception handling in McAfee Security: Antivirus VPN for Android before 8.3.0 could allow an attacker to cause a denial of service through the use of a malformed deep link. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Azure Storage Movement Client Library Denial of Service Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Standards-Based Storage Management Service Denial of Service Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
DHCP Server Service Denial of Service Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
Windows Themes Denial of Service Vulnerability. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
Aimeos is an Open Source e-commerce framework for online shops. Rated medium severity (CVSS 5.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
A heap-based buffer overflow vulnerability exists in the FOXMAN-UN/UNEM that if exploited will generally lead to a denial of service but can be used to execute arbitrary code, which is usually. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A vulnerability has been identified in SIMATIC S7-200 SMART CPU CR40 (6ES7288-1CR40-0AA0) (All versions), SIMATIC S7-200 SMART CPU CR60 (6ES7288-1CR60-0AA0) (All versions), SIMATIC S7-200 SMART CPU. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Excessive platform resource consumption within a loop issue exists in Cybozu Garoon 5.0.0 to 5.15.2. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Due to unrestricted access to the Meta Model Repository services in SAP NetWeaver AS Java, attackers can perform DoS attacks on the application, which may prevent legitimate users from accessing it. 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.
SAP NetWeaver and ABAP platform allows an attacker to impede performance for legitimate users by crashing or flooding the service. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. This Uncontrolled Resource Consumption vulnerability could allow attackers to cause denial of service by exhausting system resources.
Trend Micro VPN Proxy One Pro, version 5.8.1012 and below is vulnerable to an arbitrary file overwrite or create attack but is limited to local Denial of Service (DoS) and under specific conditions. Rated medium severity (CVSS 5.3). No vendor patch available.
A logic issue was addressed with improved file handling. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
This issue was addressed by removing the vulnerable code. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
SuiteCRM is an open-source Customer Relationship Management (CRM) software application. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
NULL pointer dereference in the Linux kernel's af_unix subsystem crashes the kernel when a local low-privilege attacker triggers a race between Unix domain socket garbage collection and out-of-band message queuing. The `__unix_gc()` function locklessly nulls `unix_sk(sk)->oob_skb` while `queue_oob()` can concurrently update the same pointer, producing a write-access fault at address 0x8 as confirmed by the supplied kernel oops trace. No public exploit identified at time of analysis, and EPSS at 0.67% (48th percentile) places real-world exploitation probability well below the severity implied by the CVSS 7.8 score.
GNOME VTE before 0.76.3 allows an attacker to cause a denial of service (memory consumption) via a window resize escape sequence, a related issue to CVE-2000-0476. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.
In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix division by zero in setup_dsc_config When slice_height is 0, the division by slice_height in the calculation. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
An XML External Entity (XXE) vulnerability in the ebookmeta.get_metadata function of lxml before v4.9.1 allows attackers to access sensitive information or cause a Denial of Service (DoS) via crafted. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An XML External Entity (XXE) vulnerability in the ebookmeta.get_metadata function of ebookmeta before v1.2.8 allows attackers to access sensitive information or cause a Denial of Service (DoS) via. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
robdns commit d76d2e6 was discovered to contain a NULL pointer dereference via the item->tokens component at /src/conf-parse.c. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
dnspod-sr 0dfbd37 contains a SEGV. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
dnspod-sr 0dfbd37 is vulnerable to buffer overflow. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity. Public exploit code available and no vendor patch available.
kubeflow/kubeflow is vulnerable to a Regular Expression Denial of Service (ReDoS) attack due to inefficient regular expression complexity in its email validation mechanism. 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 SQL Injection vulnerability exists in the berriai/litellm repository, specifically within the `/global/spend/logs` endpoint. Rated high severity (CVSS 7.2), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
A path traversal vulnerability exists in the parisneo/lollms application, specifically within the `sanitize_path_from_endpoint` and `sanitize_path` functions in `lollms_core\lollms\security.py`. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
mintplex-labs/anything-llm is affected by an uncontrolled resource consumption vulnerability in its upload file endpoint, leading to a denial of service (DOS) condition. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available.
A vulnerability in mlflow/mlflow version 2.11.1 allows attackers to create multiple models with the same name by exploiting URL encoding. Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
An issue in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Improper input validation in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An issue in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Improper input validation in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A Denial-of-Service (DoS) vulnerability exists in the `SitemapLoader` class of the `langchain-ai/langchain` repository, affecting all versions. Rated medium severity (CVSS 4.7). Public exploit code available and no vendor patch available.
A Cross-Site Request Forgery (CSRF) vulnerability exists in the profile picture upload functionality of the Lollms application, specifically in the parisneo/lollms-webui repository, affecting. Rated high severity (CVSS 8.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
parisneo/lollms-webui is vulnerable to path traversal and denial of service attacks due to an exposed `/select_database` endpoint in version a9d16b0. Rated critical severity (CVSS 9.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A remote code execution vulnerability exists in mintplex-labs/anything-llm due to improper handling of environment variables. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
An issue in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Improper input validation in OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
A TarSlip vulnerability exists in the deepjavalibrary/djl, affecting version 0.26.0 and fixed in version 0.27.0. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
An issue in the oneflow.scatter_nd parameter OneFlow-Inc. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Cyrus IMAP before 3.8.3 and 3.10.x before 3.10.0-rc1 allows authenticated attackers to cause unbounded memory allocation by sending many LITERALs in a single command. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. This Allocation of Resources Without Limits vulnerability could allow attackers to exhaust system resources through uncontrolled allocation.
Envoy is a cloud-native, open source edge and service proxy. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
Envoy is a cloud-native, open source edge and service proxy. 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.
Envoy is a cloud-native, open source edge and service proxy. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. Public exploit code available and no vendor patch available.
Envoy is a cloud-native, open source edge and service proxy. 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.
Envoy is a cloud-native, open source edge and service proxy. 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.
Envoy is a cloud-native, open source edge and service proxy. 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.
Pimcore is an Open Source Data & Experience Management Platform. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
Dell PowerScale OneFS versions 8.2.x through 9.8.0.x contain a use of hard coded credentials vulnerability. Rated high severity (CVSS 8.1), this vulnerability is no authentication required, low attack complexity. No vendor patch available.
An uncontrolled resource consumption of file descriptors in SEH Computertechnik utnserver Pro, SEH Computertechnik utnserver ProMAX, SEH Computertechnik INU-100 allows DoS via HTTP.1.22 and below. Rated high severity (CVSS 7.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Directus is a real-time API and App dashboard for managing SQL database content. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
In the Linux kernel, the following vulnerability has been resolved: thermal/debugfs: Fix two locking issues with thermal zone debug With the current thermal zone locking arrangement in the debugfs. Rated medium severity (CVSS 5.5), this vulnerability is low attack complexity.
In modem, there is a possible system crash due to improper input validation. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.