CVE-2021-1236

Publication date 13 January 2021

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
snort	26.04 LTS resolute	Not in release
	25.10 questing	Not in release
	25.04 plucky	Not in release
	24.10 oracular	Not in release
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	20.04 LTS focal	Vulnerable
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Ignored end of ESM support, was needed
	14.04 LTS trusty	Vulnerable

Notes

yomonokio

There is no access to the actual fix for this CVE nor workarounds that address this vulnerability

Severity score breakdown

CVSS version: CVSS v3.0

Base score 4.0 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Changed
Confidentiality impact	None
Integrity impact	Low
Availability impact	None

Scores

Parameter	Value
Base score	4.0 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N