Snort
CVE-2021-1224
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Protection mechanism completeness
|
| Impact | CVSS score of 5.3 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system. |
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Alert meAnalysisAI
Multiple Cisco products are affected by a vulnerability with TCP Fast Open (TFO) when used in conjunction with the Snort detection engine that could allow an unauthenticated, remote attacker to. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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Technical ContextAI · show details
This vulnerability is classified under CWE-693. Multiple Cisco products are affected by a vulnerability with TCP Fast Open (TFO) when used in conjunction with the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect detection of the HTTP payload if it is contained at least partially within the TFO connection handshake. An attacker could exploit this vulnerability by sending crafted TFO packets with an HTTP payload through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets and deliver a malicious payload. Affected products include: Cisco Firepower Threat Defense, Cisco Secure Firewall Management Center, Cisco Ios Xe, Snort, Cisco Meraki Mx64 Firmware.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Multiple Cisco products are affected by a vulnerability with TCP Fast Open (TFO) when used in conjunction with the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP. The vulnerability is due to incorrect detection of the HTTP payload if it is contained at least partially within the TFO connection handshake. An attacker could exploit this vulnerability by sending crafted TFO packets with an HTTP payload through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets and deliver a malicious payload.
Threat Intelligence Overview
NVD
CVE.org
EPSS
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.
Affected Products (CPE)NVD
Untrusted search path vulnerability in Snort 2.9.7.0-WIN32 allows remote attackers to execute arbitrary code and conduct
A buffer under-read in the Snort 3 HTTP decoder lets unauthenticated, remote attackers crash the detection engine or exp
Multiple Cisco products are affected by a vulnerability in the rate filtering feature of the Snort detection engine that
Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic tha
Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticate
Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attac
Cisco Sourcefire Snort 3.0 before build 233 mishandles Ether Type Validation. Rated high severity (CVSS 7.5), this vulne
Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticate
Denial of service in Cisco Snort 3 allows unauthenticated remote attackers to force the detection engine to restart by s
Multiple Cisco products are affected by a vulnerability in the Snort Intrusion Prevention System (IPS) rule engine that
Cisco Snort 3 Detection Engine can be remotely restarted by an unauthenticated attacker through crafted HTTP packets exp
Unauthenticated remote attackers can crash the Snort 3 Detection Engine by sending crafted HTTP packets with malformed M
GitHub PoC
Exploit-DB