CVE-2026-54388

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/tinyproxy/tinyproxy/commit/364cdb67e0ea00a8e4a7037e2693e0711e816adb
https://github.com/tinyproxy/tinyproxy/issues/609
https://github.com/tinyproxy/tinyproxy/pull/610
https://www.vulncheck.com/advisories/tinyproxy-http-request-smuggling-via-duplicate-content-length-headers
https://github.com/tinyproxy/tinyproxy/issues/609

Configurations

No configuration.

History

18 Jun 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-17 20:17

Updated : 2026-06-22 18:43

NVD link : CVE-2026-54388

Mitre link : CVE-2026-54388

CVE.ORG link : CVE-2026-54388

JSON object : View

Products Affected

No product.

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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