{"id":"CVE-2026-11404","aliases":["DEBIAN-CVE-2026-11404","EUVD-2026-42605","GHSA-cvgj-gr8r-q762","JLSEC-2026-1257","UBUNTU-CVE-2026-11404"],"status":"published","title":"Cesanta Mongoose Out-of-Bounds Read in MG_TLS_BUILTIN ClientHello Session ID Parsing","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","severity":{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00784,"percentile":0.56493,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-125"],"published":"2026-07-09T15:13:40Z","modified":"2026-11-04T10:46:25Z","fixes":[{"ecosystem":"Debian:14","package":"mongoose","fixed_in":["7.22+ds-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:14","package":"mongoose","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.22+ds-1"}]}],"versions":["7.21+ds-1","7.21+ds-1~bpo13+1","7.21+ds-2","7.22+ds-1~bpo13+1"]},{"source":"osv","ecosystem":"Julia","package":"Mongoose_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"mongoose","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.21+ds-1","7.21+ds-2","7.22+ds-1","7.23+ds-1"]}],"products":[{"vendor":"automattic","product":"mongoose"},{"vendor":"cesanta","product":"mongoose"}],"references":[{"url":"https://github.com/cesanta/mongoose/releases/tag/7.22","tags":["patch","release-notes","fix","web","report"]},{"url":"https://github.com/cesanta/mongoose","tags":["product","package","web","report"]},{"url":"https://www.vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsing","tags":["third-party-advisory","advisory","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-11404","tags":["advisory","web"]},{"url":"https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3","tags":["web","report"]},{"url":"https://github.com/advisories/GHSA-cvgj-gr8r-q762","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11404.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-11404","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-11404","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-11404","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-11404","title":"Cesanta Mongoose Out-of-Bounds Read in MG_TLS_BUILTIN ClientHello Session ID Parsing","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T15:13:40.148Z","modified":"2026-11-03T20:28:40.302Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-125"],"updated_at":"2026-11-03T22:58:37.667595Z"}],"euvd":[{"id":"EUVD-2026-42605","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T15:13:40Z","modified":"2026-11-03T20:28:40Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-03T21:20:12.603156Z"}],"ghsa":[{"id":"GHSA-cvgj-gr8r-q762","title":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function...","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T18:31:50Z","modified":"2026-07-09T18:31:51Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T15:09:22.189239Z"}],"nvd":[{"id":"CVE-2026-11404","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T16:16:34.64Z","modified":"2026-11-03T21:17:03.62Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-125"],"updated_at":"2026-11-04T00:48:02.490955Z"}],"osv":[{"id":"CVE-2026-11404","title":"Cesanta Mongoose Out-of-Bounds Read in MG_TLS_BUILTIN ClientHello Session ID Parsing","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T15:13:40.148Z","modified":"2026-11-05T08:04:50.90679251Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-125"],"updated_at":"2026-11-05T09:08:14.330889Z"},{"id":"DEBIAN-CVE-2026-11404","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T16:16:34.64Z","modified":"2026-11-04T09:47:29.72541572Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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":"high"}],"updated_at":"2026-11-04T10:05:32.187009Z"},{"id":"JLSEC-2026-1257","title":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function...","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function `mg_tls_server_recv_hello()`, which uses an attacker-controlled `session_id_len` byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on `MG_TLS_BUILTIN`.","status":"published","published":"2026-08-12T07:17:34.116Z","modified":"2026-08-12T07:43:45.65651746Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/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":"high"}],"updated_at":"2026-11-02T15:47:18.159338Z"},{"id":"UBUNTU-CVE-2026-11404","description":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.","status":"published","published":"2026-07-09T16:16:00Z","modified":"2026-10-17T12:58:04.201061197Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T16:55:59.591851Z"}]}}