CVE-2025-12642

lighttpd1.4.80 incorrectly merged trailer fields into headersafter 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