CVE-2026-54388
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk35th percentile - higher than 35% of all known CVEs
Summary
Tinyproxy through version 1.11.3 fails to reject requests containing multiple Content-Length headers with differing values, forwarding all duplicate headers to the backend while using the first value 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.
Risk Assessment
The organization is exposed to request smuggling attacks that can lead to cache poisoning, access control bypass, and session hijacking, compromising data integrity and confidentiality.
Recommendation
Immediately upgrade Tinyproxy to a version containing commit 364cdb6 or later, which rejects requests with multiple Content-Length headers having differing values.
Original NVD description (English source)
Tinyproxy through 1.11.3, fixed in commit 364cdb6, fails to reject requests containing multiple Content-Length headers with differing values, forwarding all duplicate headers to the backend while using the first value 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.