{"cve":"CVE-2025-12642","nvd":{"published":"2025-11-03T20:17:06.410","modified":"2026-10-19T13:10:00.110","status":"Analyzed","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.\n\nSuccessful exploitation may allow an attacker to:\n\n  *  Bypass access control rules\n  *  Inject unsafe input into backend logic that trusts request headers\n  *  Execute HTTP Request Smuggling attacks under some conditions\n\n\nThis issue affects lighttpd1.4.80","cvss_v4":{"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","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-444"],"references":["https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1"],"products":["lighttpd:lighttpd"],"source":"nvd","synced_at":"2026-10-19T22:14:53.307938015+00:00"},"epss":{"cve":"CVE-2025-12642","score":0.00368,"percentile":0.30399,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}