Bug 2558481 (CVE-2026-111816)

Summary: CVE-2026-111816 trafficserver: Apache Traffic Server: A malformed 302 response bypasses parse-error rejection through the Transfer-Encoding: chunked carve-out
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Apache Traffic Server. Malformed HTTP 302 redirect responses containing chunked transfer encoding are improperly forwarded instead of being rejected as parse errors. A remote attacker can exploit this condition to cause HTTP response desynchronization and cache poisoning, potentially resulting in data tampering or unauthorized content delivery to other users.
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Description OSIDB Bzimport 2026-10-21 18:52:35 UTC 
Apache Traffic Server forwarded a malformed 302 response that should have been rejected as a parse error, because the Transfer-Encoding: chunked carve-out bypassed the rejection path. A response that two peers can read differently is then stored and served, allowing cache poisoning and response-framing desync.



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.