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Vulnerability details: VCID-nm33-umft-9fa6
Vulnerability ID VCID-nm33-umft-9fa6
Aliases CVE-2025-12642
Summary 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
Status Published
Exploitability None
Weighted Severity None
Risk None
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
System Score Found at
epss 0.00064 https://api.first.org/data/v1/epss?cve=CVE-2025-12642
cvssv4 6.9 https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
ssvc Track https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2025-12642
35cb89c103877de62d6b63d0804255475d77e5e1 https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
No exploits are available.
Vector: 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 Found at https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

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Vector: SSVCv2/E:N/A:Y/T:P/P:M/B:A/M:M/D:T/2025-11-03T19:43:55Z/ Found at https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1
Exploit Prediction Scoring System (EPSS)
Percentile 0.2017
EPSS Score 0.00064
Published At May 29, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-05-29T16:57:13.174762+00:00 Debian Importer Import https://security-tracker.debian.org/tracker/data/json 38.6.0