CVE-2025-12642

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

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1	Patch

Configurations

Configuration 1 (hide)

cpe:2.3:a:lighttpd:lighttpd:1.4.80:*:*:*:*:*:*:*

History

12 Nov 2025, 14:34

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.1
CPE		cpe:2.3:a:lighttpd:lighttpd:1.4.80:::::::*
References	~~() https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1 -~~	() https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1 - Patch
First Time		Lighttpd Lighttpd lighttpd

03 Nov 2025, 20:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2025-11-03 20:17

Updated : 2025-11-12 14:34

NVD link : CVE-2025-12642

Mitre link : CVE-2025-12642

CVE.ORG link : CVE-2025-12642

JSON object : View

Products Affected

lighttpd

lighttpd

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

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