CVE-2026-54388
Tinyproxy - HTTP Request Smuggling via Duplicate Content-Length Headers
CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-444 |
| Vendor | tinyproxy |
| Product | tinyproxy |
| Published | Jun 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
tinyproxy / tinyproxy
0 ≤ 1.11.3
References
github.com: https://github.com/tinyproxy/tinyproxy/issues/609 github.com: https://github.com/tinyproxy/tinyproxy/pull/610 github.com: https://github.com/tinyproxy/tinyproxy/commit/364cdb67e0ea00a8e4a7037e2693e0711e816adb vulncheck.com: https://www.vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-duplicate-content-length-headers
Credits
Tristan Madani (@TristanInSec)