Is CVE-2026-54388 actively exploited?

No active exploitation of CVE-2026-54388 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-54388 be exploited remotely?

Yes. CVE-2026-54388 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-54388?

CVE-2026-54388 has a CVSS score of 9.1 (CRITICAL).

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CRITICAL

CVE-2026-54388

CWE-444Published: June 17, 2026· Updated: Jun 22, 2026

9.1

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2026-54388 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 9.1.