CVE-2021-1224

Low

No strong exploitation signal.

CVSS base

5.8 MEDIUM

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

EPSS — probability of exploitation (30 days)

2.0%

79.9th percentile

CISA KEV

Not listed

Weakness / dates

CWE-693

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

CVSS breakdown

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

Attack Vector	N	Network
Attack Complexity	L	Low
Privileges Required	N	None
User Interaction	N	None
Scope	C	Changed
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 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

cisco snort

References

Official: NVD · CVE.org