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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Cisco | Cisco Firepower Threat Defense Software | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 11 | snort | 2.9.20-0+deb11u1 | DSA-5354-1 |
| Debian 10 | snort | 2.9.20-0+deb10u1 | DLA-3317-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | snort | No fix yet | — |
| Ubuntu 20.04 LTS | snort | No fix yet | — |
| Ubuntu 18.04 LTS | snort | No fix yet | — |
| Ubuntu 16.04 LTS | snort | No fix yet | — |
| Ubuntu 14.04 LTS | snort | No fix yet | — |
Advisories 3
- DSA-5354-1 snort - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3317-1 snort - security update Debian Security (DSA / DLA) · Mar 9, 2026
- WID-SEC-2023-0339 Snort: Mehrere Schwachstellen ermöglichen Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Feb 19, 2023
References
- 20210113 Multiple Cisco Products Snort TCP Fast Open File Policy Bypass Vulnerability vendor-advisory
- [debian-lts-announce] 20230210 [SECURITY] [DLA 3317-1] snort security update mailing-list
- DSA-5354 vendor-advisory