Bug 2558489 (CVE-2026-111809)

Summary: CVE-2026-111809 trafficserver: Apache Traffic Server: HEAD requests carrying Content-Length or Transfer-Encoding enable request smuggling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Apache Traffic Server. An unauthenticated remote attacker can exploit this vulnerability by sending specially crafted HEAD requests containing Content-Length or Transfer-Encoding headers. This flaw enables HTTP request smuggling, where intermediate proxies and backend servers disagree on request boundaries. Successful exploitation may allow an attacker to bypass security boundaries, poison web caches, or hijack user requests.
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Description OSIDB Bzimport 2026-10-21 19:21:39 UTC 
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.