CVE-2026-54387
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk35th percentile - higher than 35% of all known CVEs
Summary
Tinyproxy up to version 1.11.3 fails to reconcile conflicting Content-Length and Transfer-Encoding: chunked headers, forwarding both to the backend while using Content-Length to determine request body bytes. Remote attackers can desynchronize proxy and backend parser states, enabling injection of arbitrary HTTP requests to the backend.
Risk Assessment
Attackers can poison caches, bypass access controls, and hijack user requests, leading to confidentiality and integrity breaches.
Recommendation
Immediately upgrade Tinyproxy to a version containing commit ff45d3b or later, which fixes this vulnerability.
Original NVD description (English source)
Tinyproxy through 1.11.3, fixed in commit ff45d3b, fails to reconcile conflicting Content-Length and Transfer-Encoding: chunked headers, forwarding both verbatim to the backend while using Content-Length to determine how many request body bytes to consume. Remote attackers can desynchronize the proxy and backend parser state, allowing injection of arbitrary HTTP requests to the backend to enable cache poisoning, access control bypass, and request hijacking.