HTTP Header Smuggling via Trailer Merge_CVE-2025-12642

6.9 / 10

MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

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

Basic Information

ID CVE-2025-12642

Source Toreon

Published Nov 3, 2025 at 19:36

Modified Nov 3, 2025 at 19:44

Affected Product

Vendor lighttpd

Product lighttpd

Version 1.4.80

Affected Versions lighttpd lighttpd 1.4.80

CWE Classification

CWE-444

References

github.com /lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1

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    "published": "2025-11-03T19:36:17.011Z",
    "modified": "2025-11-03T19:44:09.174Z",
    "type": "cve",
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