CVE-2026-54387
CRITICALTinyproxy - HTTP Request Smuggling via CL/TE Desynchronization
Title source: cnaDescription
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.
References (4)
Core 4
Core References
Technical Description technical-description
Researcher Pull Request
https://github.com/tinyproxy/tinyproxy/issues/609
Issue Tracking issue-tracking
Maintainer Pull Request
https://github.com/tinyproxy/tinyproxy/pull/610
Patch patch
Patch Commit
https://github.com/tinyproxy/tinyproxy/commit/ff45d3bf0e61d0f8ed97ab379d3047f04eb67521
Third Party Advisory third-party-advisory
https://www.vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-cl-te-desynchronization
Scores
CVSS v3
9.1
EPSS
0.0039
EPSS Percentile
30.1%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
total
Details
CWE
CWE-444
Status
published
Products (2)
tinyproxy/tinyproxy
< 1.11.3
tinyproxy/tinyproxy
ff45d3bf0e61d0f8ed97ab379d3047f04eb67521
Published
Jun 17, 2026
Tracked Since
Jun 18, 2026