CVE-2021-1236

Low

No strong exploitation signal.

CVSS base

5.3 MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS — probability of exploitation (30 days)

2.1%

81.3th percentile

CISA KEV

Not listed

Weakness / dates

CWE-670

Published 2021-01-13 · modified 2026-08-11

CVSS breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector	N	Network
Attack Complexity	L	Low
Privileges Required	N	None
User Interaction	N	None
Scope	U	Unchanged
Confidentiality	N	None
Integrity	L	Low
Availability	N	None

Timeline

2021-01-13 — Published (NVD)
2026-08-11 — Last modified (NVD)

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.

Affected

cisco snort

References

Official: NVD · CVE.org