CVE-2025-12642 – HTTP Header Smuggling via Trailer Merge

CVE ID : CVE-2025-12642

Published : Nov. 3, 2025, 8:17 p.m. | 1 hour, 11 minutes ago

Description : lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks.

Successful exploitation may allow an attacker to:

* Bypass access control rules
* Inject unsafe input into backend logic that trusts request headers
* Execute HTTP Request Smuggling attacks under some conditions

This issue affects lighttpd1.4.80

Severity: 6.9 | MEDIUM

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