{"id":"JLSEC-2026-1257","summary":"Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function...","details":"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`.","modified":"2026-08-12T07:43:45.656517460Z","published":"2026-08-12T07:17:34.116Z","upstream":["CVE-2026-11404","EUVD-2026-42605","GHSA-cvgj-gr8r-q762"],"database_specific":{"license":"CC-BY-4.0","sources":[{"imported":"2026-08-10T09:19:09.074Z","modified":"2026-07-28T03:16:43.060Z","published":"2026-07-09T16:16:34.640Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-11404","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2026-11404","database_specific":{"status":"Deferred"},"id":"CVE-2026-11404"},{"published":"2026-07-09T18:31:50Z","url":"https://api.github.com/advisories/GHSA-cvgj-gr8r-q762","html_url":"https://github.com/advisories/GHSA-cvgj-gr8r-q762","id":"GHSA-cvgj-gr8r-q762","imported":"2026-08-10T09:19:09.947Z","modified":"2026-07-09T18:31:51Z"},{"html_url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-42605","id":"EUVD-2026-42605","imported":"2026-08-10T09:18:49.356Z","modified":"2026-07-28T01:48:21Z","published":"2026-07-09T15:13:40Z","url":"https://euvdservices.enisa.europa.eu/api/enisaid?id=EUVD-2026-42605"}]},"references":[{"type":"WEB","url":"https://github.com/advisories/GHSA-cvgj-gr8r-q762"},{"type":"WEB","url":"https://github.com/cesanta/mongoose"},{"type":"WEB","url":"https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3"},{"type":"WEB","url":"https://github.com/cesanta/mongoose/releases/tag/7.22"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-11404"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsing"}],"affected":[{"package":{"name":"Mongoose_jll","ecosystem":"Julia","purl":"pkg:julia/Mongoose_jll?uuid=0a8a3f5b-4c0e-5906-8e29-5b3fee15539c"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-1257.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"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"}]}