{"id":"CVE-2025-12642","state":"PUBLISHED","title":"HTTP Header Smuggling via Trailer Merge","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","publishedAt":"2025-11-03T19:36:17.011Z","updatedAt":"2025-11-03T19:44:09.174Z","severity":{"score":6.9,"label":"Medium","version":"4.0","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","source":"Toreon"},"assigner":"Toreon","products":["lighttpd lighttpd"],"affected":[{"vendor":"lighttpd","product":"lighttpd","packageName":"lighttpd1.4","defaultStatus":"unaffected","versions":[{"version":"1.4.80","status":"affected","lessThan":"1.4.81","versionType":"custom"}],"modules":["mod_proxy"],"repo":"https://git.lighttpd.net/lighttpd/lighttpd1.4"}],"references":["https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1"],"weaknesses":["CWE-444"],"ingestedAt":"2026-10-29T20:08:31.050Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/12xxx/CVE-2025-12642.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-12642","state":"PUBLISHED","datePublished":"2025-11-03T19:36:17.011Z","dateUpdated":"2025-11-03T19:44:09.174Z","assignerShortName":"Toreon","assignerOrgId":"1c6b5737-9389-4011-8117-89fa251edfb2","dateReserved":"2025-11-03T19:34:17.666Z"},"containers":{"cna":{"title":"HTTP Header Smuggling via Trailer Merge","descriptions":[{"lang":"en","value":"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"}],"affected":[{"vendor":"lighttpd","product":"lighttpd","packageName":"lighttpd1.4","defaultStatus":"unaffected","versions":[{"version":"1.4.80","status":"affected","lessThan":"1.4.81","versionType":"custom"}],"modules":["mod_proxy"],"repo":"https://git.lighttpd.net/lighttpd/lighttpd1.4"}],"references":[{"url":"https://github.com/lighttpd/lighttpd1.4/commit/35cb89c103877de62d6b63d0804255475d77e5e1"}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":6.9,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"LOW","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","description":"CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"Toreon","orgId":"1c6b5737-9389-4011-8117-89fa251edfb2","dateUpdated":"2025-11-03T19:36:17.011Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:lighttpd:lighttpd:*:*:*:*:*:*:*:*","versionEndExcluding":"1.4.81","versionStartIncluding":"1.4.80","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"OR"}],"credits":[{"lang":"en","type":"finder","value":"Sebastiano Sartor <@sebsrt>"}],"impacts":[{"capecId":"CAPEC-554","descriptions":[{"lang":"en","value":"CAPEC-554 Functionality Bypass"}]},{"capecId":"CAPEC-33","descriptions":[{"lang":"en","value":"CAPEC-33 HTTP Request Smuggling"}]}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 0.4.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2025-11-03T19:43:55.914894Z","id":"CVE-2025-12642","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-11-03T19:44:09.174Z"}}]}}}