by Kastro
Paper/Archive/CVE-2026-54388

CVE-2026-54388

tinyproxy tinyproxy — Tinyproxy - HTTP Request Smuggling via Duplicate Content-Length Headers

EPSS 0.4%public exploitCVSS 9.3
critical.is priorityof 100
46
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 38.1.381 × 207.6Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
tinyproxy≤ 1.11.3364cdb67e0ea00a8e4a7037e2693e0711e816adbCNA

Scores by source

VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
VulnCheck (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/tinyproxy/tinyproxy/issues/609refgithub.com/tinyproxy/tinyproxy/pull/610patchgithub.com/tinyproxy/tinyproxy/commit/364cdb67e0ea00a8e4a7037e2693e0711e816adbwriteupvulncheck.com/advisories/tinyproxy-http-request-smuggling-via-duplicate-content-length-headers