Is CVE-2026-40562 actively exploited?

No active exploitation of CVE-2026-40562 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-40562 be exploited remotely?

Yes. CVE-2026-40562 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-40562?

CVE-2026-40562 has a CVSS score of 7.5 (HIGH).

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HIGH

CVE-2026-40562

CWE-444Published: May 6, 2026· Updated: May 11, 2026

7.5

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:7.8th

Official Description

Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence.

Gazelle incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence.

An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.

NVD Source

Technical Analysis

CVE-2026-40562 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 full integrity compromise (data manipulation), with a CVSS base score of 7.5.