CVE-2026-40562
Published: 06 May 2026
Summary
CVE-2026-40562 is a high-severity HTTP Request/Response Smuggling (CWE-444) vulnerability in Kazeburo Gazelle. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 13.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-27825
Vulnerability details
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…
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could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
HTTP request smuggling via header precedence flaw directly enables exploitation of the public-facing Perl web application (and proxy bypass).
CVEs Like This One
Affected Assets
Mitigating Controls
No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.