{"id":"CVE-2026-73260","aliases":["DEBIAN-CVE-2026-73260","EUVD-2026-101597","GHSA-f6wr-mg35-p25g","UBUNTU-CVE-2026-73260"],"status":"published","title":"Mongoose: Out-of-bounds Read via length-counter underflow in built-in TLS X.509 DER parser","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","severity":{"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","from":"cve"},"epss":{"day":"2026-11-12","score":0.0023,"percentile":0.13964,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-125"],"published":"2026-10-14T18:25:00Z","modified":"2026-10-28T20:17:48Z","fixes":[{"ecosystem":"Debian:14","package":"mongoose","fixed_in":["7.23+ds-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:14","package":"mongoose","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.23+ds-1"}]}],"versions":["7.21+ds-1","7.21+ds-1~bpo13+1","7.21+ds-2","7.22+ds-1","7.22+ds-1~bpo13+1","7.23+ds-1~bpo13+1"]},{"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/security/advisories/GHSA-f6wr-mg35-p25g","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/cesanta/mongoose/releases/tag/7.23","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73260.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73260","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-73260","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-73260","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-73260","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-73260","title":"Mongoose: Out-of-bounds Read via length-counter underflow in built-in TLS X.509 DER parser","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T18:25:00.518Z","modified":"2026-10-20T01:50:00.898Z","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","assessor":"cna"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T13:43:33.766176Z"}],"euvd":[{"id":"EUVD-2026-101597","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T18:25:00Z","modified":"2026-10-20T01:50:00Z","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"}],"updated_at":"2026-11-02T16:59:44.89597Z"}],"nvd":[{"id":"CVE-2026-73260","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T19:17:19.84Z","modified":"2026-10-20T02:17:11.72Z","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","assessor":"secondary"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T14:12:59.328869Z"}],"osv":[{"id":"CVE-2026-73260","title":"Mongoose: Out-of-bounds Read via length-counter underflow in built-in TLS X.509 DER parser","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T18:25:00.518Z","modified":"2026-10-28T11:23:03.795879736Z","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"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T15:45:16.365946Z"},{"id":"DEBIAN-CVE-2026-73260","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T19:17:19.84Z","modified":"2026-10-23T17:47:47.556570771Z","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"}],"updated_at":"2026-11-02T15:46:02.499355Z"},{"id":"UBUNTU-CVE-2026-73260","description":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS certificate parser selected by MG_TLS_BUILTIN fails to verify that a long-form DER element length fits within the remaining certificate buffer. In mg_der_to_tlv() and mg_der_next(), a peer-controlled length can advance the parser beyond the certificate and underflow the remaining uint32_t length, causing mg_tls_parse_cert_der() to continue walking an invalid pointer. An unauthenticated malicious TLS server, or a client presenting a certificate to a server configured for client certificates, can trigger an out-of-bounds read and denial of service during the handshake. This issue is fixed in version 7.23.","status":"published","published":"2026-10-14T19:17:00Z","modified":"2026-10-28T20:17:48.062260358Z","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"}],"updated_at":"2026-11-02T16:57:08.628462Z"}]}}