PT-2026-50538 · Tinyproxy · Tinyproxy

Tristan Madani · Published 2026-06-17 · Updated 2026-06-17 · CVE-2026-54387

Mitre

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

Fix

HTTP Request/Response Smuggling

Weakness Enumeration

CWE-444

Related Identifiers

CVE-2026-54387

Affected Products

Tinyproxy

References · 4

• https://github.com/tinyproxy/tinyproxy/commit/ff45d3bf0e61d0f8ed97ab379d3047f04eb67521 · Patch
• https://github.com/tinyproxy/tinyproxy/pull/610 · Note
• https://github.com/tinyproxy/tinyproxy/issues/609 · Note
• https://vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-cl-te-desynchronization · Note