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Vulnerability DatabaseCVE-2025-12642

CVE-2025-12642: 
lighttpd vulnerability analysis and mitigation

Overview

CVE-2025-12642 affects lighttpd version 1.4.80, where the software incorrectly merged trailer fields into headers after HTTP request parsing. The vulnerability was discovered in November 2025 and was reported by Toreon (NVD, Ubuntu).

Technical details

The vulnerability is classified as CWE-444 (Inconsistent Interpretation of HTTP Requests - HTTP Request/Response Smuggling). It has received a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N, and a CVSS v4.0 score of 6.9 (MEDIUM) (NVD).

Impact

Successful exploitation of this vulnerability can lead to multiple security issues including bypass of access control rules, injection of unsafe input into backend logic that trusts request headers, and execution of HTTP Request Smuggling attacks under certain conditions (NVD).

Mitigation and workarounds

A patch has been released to fix this vulnerability in lighttpd version 1.4.81. The fix involves rejecting disallowed trailers in the HTTP request processing (Lighttpd Patch).

Additional resources

Source: This report was generated using AI

Related lighttpd vulnerabilities:

CVE ID

Severity

Score

Technologies

Component name

CISA KEV exploit

Has fix

Published date

CVE-2024-3094CRITICAL10
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NoYesMar 29, 2024
CVE-2025-8671HIGH7.5
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CVE-2022-41556HIGH7.5
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CVE-2025-12642MEDIUM6.9
  • lighttpdlighttpd
  • lighttpd
NoNoNov 03, 2025
CVE-2018-25103MEDIUM5.3
  • lighttpdlighttpd
  • lighttpd
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