Bug 2558469 (CVE-2025-31699)

Summary: CVE-2025-31699 trafficserver: Apache Traffic Server: Origin connection still owed a request body is reused, enabling request smuggling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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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 send a request with an incomplete body, causing an origin connection to be prematurely returned to the shared pool while the backend is still awaiting data. When a subsequent request is processed over that reused connection, the backend interprets it as leftover body data. This allows the attacker to perform HTTP request smuggling to bypass access controls, poison shared web caches, or disrupt other users' traffic.
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Description OSIDB Bzimport 2026-10-21 18:39:46 UTC 
Apache Traffic Server can return an origin connection to the shared pool while the origin is still waiting on a request body the client declared but never fully sent, including when the client used Expect: 100-continue. The origin then reads a later request on that connection as leftover body data, which lets an attacker smuggle requests past ATS access controls, disrupt other users' requests, or poison the cache.



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.