CVE-2026-111809

Apache Traffic Server: HEAD requests carrying Content-Length or Transfer-Encoding enable request smuggling

State: Published
Severity: 6.9 Medium
Published: Oct 21, 2026
Updated: Oct 28, 2026
Reserved: Oct 16, 2026

Description

Apache Traffic Server allows request smuggling via HEAD requests that carry Content-Length or Transfer-Encoding.

This issue affects Apache Traffic Server: from 8.0.0 through 8.1.11, from 9.0.0 through 9.2.15, from 10.0.0 through 10.1.4, 10.2.0.

Users are recommended to upgrade to version 9.2.16, 10.1.5, or 10.2.1, which fix the issue.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N	apache
3.1	9.3 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N	apache

Weaknesses

CWE-444 Inconsistent Interpretation of HTTP Requests

Affected Products

Product	Versions
Apache Traffic ServerApache Software Foundation	8.0.0 through 8.1.11Affected 9.0.0 through 9.2.15Affected 10.0.0 through 10.1.4Affected 10.2.0Affected

References

https://lists.apache.org/thread/r95dq29ywcd1f4x30snxlqmb12z4s4kcvendor-advisory

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