Vulnerability Report

CVE-2021-1236

Title: Cisco Snort Application Detection Engine Policy Bypass

Other

Proof Of Concept

No public PoC currently indexed for CVE-2021-1236.

CWE Category CWE-670
Published Date Jan 13, 2021
Modified Date Aug 11, 2026
Exploit Status Not Found
Score 5.3 CVSS v3.1
Exploit Probability (EPSS)
2.15%

Vulnerability Summary

CVE-2021-1236: Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network.

Impacted Vendors

S
snort 1
M
martin_roesch 1
C
cisco 19

Reference Links

https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq https://www.debian.org/security/2023/dsa-5354 https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq https://www.debian.org/security/2023/dsa-5354
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
5.3
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v3.0
Source Entity [email protected]
Severity MEDIUM
4.0
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:N/I:P/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-1236 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected Stack

No specific products linked.