Bug 2558464 (CVE-2025-55702)

Summary: CVE-2025-55702 trafficserver: Apache Traffic Server: HTTP request smuggling via unread POST request body
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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Hardware: All   
OS: Linux   
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A flaw was found in Apache Traffic Server. When a client sends a POST request with an Expect header and the origin server responds before consuming the full body, Traffic Server incorrectly parses the remaining unread body as a subsequent request. A remote attacker behind a front-end proxy sharing connections can exploit this issue to perform HTTP request smuggling, enabling them to bypass front-end security boundaries and access or tamper with responses intended for other users.
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Bug Depends On: 2562329, 2562331    
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Description OSIDB Bzimport 2026-10-21 18:36:14 UTC 
When a client sends a POST with Expect: 100-continue and the origin answers before reading the body, Apache Traffic Server parses the unread body left on the client connection as the next request. An attacker behind a front-end proxy that shares connections to Traffic Server can use this to smuggle requests past the front end and desynchronize responses for other users.



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.