{"id":"CVE-2026-124040","aliases":["AZL-113116","DEBIAN-CVE-2026-124040","EUVD-2026-118441","GHSA-wj2x-x5pc-4h8r","UBUNTU-CVE-2026-124040"],"status":"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.","severity":{"version":"4.0","score":9.2,"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","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00514,"percentile":0.44337,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-416"],"published":"2026-11-06T19:14:48Z","modified":"2026-11-11T14:17:31Z","exploits":[{"source":"pocgithub","id":"zeetee1235/CVE-2026-124040","title":"zeetee1235/CVE-2026-124040","date":"2026-11-08","url":"https://github.com/zeetee1235/CVE-2026-124040"}],"affected":[{"source":"osv","ecosystem":"Azure Linux:3","package":"ceph","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"18.2.2-13"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.15+dfsg-4","1.16+dfsg-1","1.16+dfsg-2","1.16+dfsg-3","1.16+dfsg-4","1.16+dfsg-5","1.16+dfsg-6"]},{"source":"osv","ecosystem":"Debian:13","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16+dfsg-2","1.16+dfsg-2+deb13u1","1.16+dfsg-3","1.16+dfsg-4","1.16+dfsg-5","1.16+dfsg-6"]},{"source":"osv","ecosystem":"Debian:14","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16+dfsg-2","1.16+dfsg-3","1.16+dfsg-4","1.16+dfsg-5","1.16+dfsg-6"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.13+dfsg-5","1.15+dfsg-1","1.15+dfsg-3","1.15+dfsg-3ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16+dfsg-1","1.16+dfsg-1build1","1.16+dfsg-1ubuntu0.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16+dfsg-3","1.16+dfsg-4"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"civetweb","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.16+dfsg-2","1.16+dfsg-3","1.16+dfsg-3ubuntu0.1"]}],"products":[{"vendor":"civetweb","product":"civetweb"}],"references":[{"url":"https://github.com/civetweb/civetweb/issues/1379","tags":["issue-tracking","report"]},{"url":"https://github.com/civetweb/civetweb","tags":["product","package","report"]},{"url":"https://github.com/civetweb/civetweb/blob/v1.16/src/http2.inl#L1574-L1581","tags":["technical-description","article","report"]},{"url":"https://www.vulncheck.com/advisories/civetweb-through-1.16-http-2-use-after-free-via-stale-pseudo-header-state","tags":["third-party-advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-124040","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-wj2x-x5pc-4h8r"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/124xxx/CVE-2026-124040.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-124040","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-124040","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-124040","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-124040","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.","status":"published","published":"2026-11-06T19:14:48.975Z","modified":"2026-11-11T03:24:56.121Z","cvss":[{"version":"4.0","score":9.2,"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","level":"critical","assessor":"cna"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-416"],"updated_at":"2026-11-11T04:22:54.647883Z"}],"euvd":[{"id":"EUVD-2026-118441","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.","status":"published","published":"2026-11-06T19:14:48Z","modified":"2026-11-11T03:24:56Z","cvss":[{"version":"4.0","score":9.2,"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","level":"critical"}],"updated_at":"2026-11-07T00:07:45.032755Z"}],"ghsa":[{"id":"GHSA-wj2x-x5pc-4h8r","title":"CivetWeb through 1.16, when built with USE_HTTP2 and enable_http2 on, contains a use-after-free...","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.","status":"published","published":"2026-11-06T21:31:31Z","modified":"2026-11-06T21:31:37Z","cvss":[{"version":"4.0","score":9.2,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-416"],"updated_at":"2026-11-06T21:34:16.869182Z"}],"nvd":[{"id":"CVE-2026-124040","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.","status":"published","published":"2026-11-06T20:17:22.203Z","modified":"2026-11-11T05:19:35.63Z","cvss":[{"version":"4.0","score":9.2,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical","assessor":"secondary"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-416"],"updated_at":"2026-11-11T07:23:50.259917Z"}],"osv":[{"id":"CVE-2026-124040","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.","status":"published","published":"2026-11-06T19:14:48.975Z","modified":"2026-11-08T02:47:32.589825892Z","cvss":[{"version":"4.0","score":9.2,"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","level":"critical"}],"cwes":["CWE-416"],"updated_at":"2026-11-08T02:57:14.556074Z"},{"id":"DEBIAN-CVE-2026-124040","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.","status":"published","published":"2026-11-06T20:17:22.203Z","modified":"2026-11-11T10:00:56.231752126Z","cvss":[{"version":"4.0","score":9.2,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical"}],"updated_at":"2026-11-11T10:35:16.464644Z"},{"id":"UBUNTU-CVE-2026-124040","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.","status":"published","published":"2026-11-09T00:00:00Z","modified":"2026-11-10T02:50:22.511615335Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"high"},{"version":"4.0","score":9.2,"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","level":"critical"}],"updated_at":"2026-11-10T03:18:58.105788Z"},{"id":"AZL-113116","title":"CVE-2026-124040 affecting package ceph 18.2.2-13","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.","status":"published","published":"2026-11-06T20:17:22Z","modified":"2026-11-11T14:17:31.875737454Z","updated_at":"2026-11-11T14:42:54.020399Z"}]}}