Inconsistent interpretation of HTTP requests in Apache Traffic Server - CVE-2026-111809
Published: October 23, 2026
Vulnerability identifier: #VU157331
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-111809
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to smuggle HTTP requests, potentially bypassing request-processing controls or exposing other users' data.
The vulnerability exists due to inconsistent HTTP request framing in Apache Traffic Server when handling HEAD requests carrying Content-Length or Transfer-Encoding. A remote attacker can send specially crafted HEAD requests containing these headers to exploit inconsistent message-boundary interpretation and smuggle requests, potentially bypassing controls or exposing other users' data.
Affected software
Apache Traffic Server
How to mitigate CVE-2026-111809
Install security update from vendor's website.
Apache Traffic Server - addressed in versions 9.2.16, 10.1.5, 10.2.1