{"id":"CVE-2026-73260","summary":"Mongoose: Out-of-bounds Read via length-counter underflow in built-in TLS X.509 DER parser","details":"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.","aliases":["GHSA-f6wr-mg35-p25g"],"modified":"2026-10-16T07:11:26.006092425Z","published":"2026-10-14T18:25:00.518Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-125"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73260.json"},"references":[{"type":"WEB","url":"https://github.com/cesanta/mongoose/releases/tag/7.23"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73260.json"},{"type":"ADVISORY","url":"https://github.com/cesanta/mongoose/security/advisories/GHSA-f6wr-mg35-p25g"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73260"},{"type":"FIX","url":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/cesanta/mongoose","events":[{"introduced":"0"},{"fixed":"a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e"},{"fixed":"02bdbb9ed6f0a8f7c42228c6e7cb35d748b60551"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"7.23"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["7.22","7.21","7.20","7.19","7.18","7.17","7.16","7.15","7.14","7.13","7.12","7.11","7.8","7.7","7.6","7.5","7.4","7.3","7.2","7.1","7.0","6.18","6.17","6.16","6.15","6.14","6.13","6.12","6.11","6.10","6.9","6.7","6.6","6.5","6.4","6.3","6.2","6.1","6.0","5.6","5.5_20140120","5.5","5.4","5.3","5.2","5.1","5.0","4.1","4.0","3.8","3.7","3.6","3.5","3.4","3.3","3.2"],"database_specific":{"vanir_signatures":[{"digest":{"function_hash":"213981136096248640611978943396017267651","length":610},"id":"CVE-2026-73260-85d8c789","signature_type":"Function","signature_version":"v1","source":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e","target":{"file":"src/tls_builtin.c","function":"mg_der_to_tlv"},"deprecated":false},{"source":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e","target":{"file":"mongoose.c","function":"mg_der_to_tlv"},"deprecated":false,"digest":{"function_hash":"213981136096248640611978943396017267651","length":610},"id":"CVE-2026-73260-95387f1c","signature_type":"Function","signature_version":"v1"},{"id":"CVE-2026-73260-a95e205c","signature_type":"Line","signature_version":"v1","source":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e","target":{"file":"src/tls_builtin.c"},"deprecated":false,"digest":{"line_hashes":["124394138259036225932629568363532647872","139709116596322563198480498833780995953","235360255883762955674233621175853353169","219936648244869027638078566151295136364","185077388558120852012544171801399809806","201273668825858706536625492116261927482","89306668249278182338547637447717928084","3870691890504760664170096862531715510","188729046174796049320278951550318021462","119695758224611338394967068421408468121","237204443698544197507511548931600360954","76845400444335940921878909852528792920","220767147040442188183983019327440131905"],"threshold":0.9}},{"signature_version":"v1","source":"https://github.com/cesanta/mongoose/commit/a8b4ae95db3c2db85e5ad9db3fefaeebb5f7b43e","target":{"file":"mongoose.c"},"deprecated":false,"digest":{"line_hashes":["124394138259036225932629568363532647872","139709116596322563198480498833780995953","235360255883762955674233621175853353169","219936648244869027638078566151295136364","185077388558120852012544171801399809806","201273668825858706536625492116261927482","89306668249278182338547637447717928084","3870691890504760664170096862531715510","188729046174796049320278951550318021462","119695758224611338394967068421408468121","237204443698544197507511548931600360954","76845400444335940921878909852528792920","220767147040442188183983019327440131905"],"threshold":0.9},"id":"CVE-2026-73260-d38af171","signature_type":"Line"}],"vanir_signatures_modified":"2026-10-16T07:11:26Z","source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73260.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"}]}