{"id":"CVE-2026-124040","state":"PUBLISHED","title":"CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State","description":"CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free vulnerability in handle_http2() that retains freed :method and :path pointers. Unauthenticated remote attackers can send a later HEADERS frame omitting these pseudo-headers to influence request method or path seen by access rules, or crash the server.","publishedAt":"2026-11-06T19:14:48.975Z","updatedAt":"2026-11-06T19:14:48.975Z","severity":{"score":9.2,"label":"Critical","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["civetweb civetweb"],"affected":[{"vendor":"civetweb","product":"civetweb","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.16","versionType":"custom"}]}],"references":["https://github.com/civetweb/civetweb/issues/1379","https://github.com/civetweb/civetweb","https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581","https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state"],"weaknesses":["CWE-416"],"ingestedAt":"2026-11-06T19:20:06.668Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/124xxx/CVE-2026-124040.json","commit":"64a2fc3fb51a0d352ce39f4daed428c7f43508b1","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-124040","state":"PUBLISHED","datePublished":"2026-11-06T19:14:48.975Z","dateUpdated":"2026-11-06T19:14:48.975Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-11-06T19:11:14.928Z"},"containers":{"cna":{"title":"CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State","descriptions":[{"lang":"en","value":"CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free vulnerability in handle_http2() that retains freed :method and :path pointers. Unauthenticated remote attackers can send a later HEADERS frame omitting these pseudo-headers to influence request method or path seen by access rules, or crash the server."}],"affected":[{"vendor":"civetweb","product":"civetweb","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.16","versionType":"custom"}]}],"references":[{"url":"https://github.com/civetweb/civetweb/issues/1379","tags":["issue-tracking"],"name":"GitHub Issue #1379"},{"url":"https://github.com/civetweb/civetweb","tags":["product"]},{"url":"https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581","tags":["technical-description"]},{"url":"https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state","name":"VulnCheck Advisory: CivetWeb through 1.16 HTTP/2 Use-After-Free via Stale Pseudo-Header State","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":9.2,"baseSeverity":"CRITICAL"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","description":"Use After Free","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-11-06T19:14:48.975Z"},"datePublic":"2026-03-18T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:civetweb_project:civetweb:*:*:*:*:*:*:*:*","versionEndIncluding":"1.16"}]}]}],"credits":[{"lang":"en","value":"PuH4ck3rX","type":"finder"},{"lang":"en","value":"Lee Keon-Hyeong","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}}}}}