{"id":"CVE-2026-73252","title":"Mongoose is an embedded web server and network library","summary":"Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS stack selected by MG_TLS_BUILTIN in src/tls_builtin.c accepts a TLS 1.3 record whose decrypted size is exactly the 16-byte authentication tag with no…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-125","CWE-191"],"vendor":"cesanta","product":"mongoose","affected":["mongoose < 7.23"],"published":"2026-10-14","updated":"2026-10-16","sourceUpdated":"2026-10-16T20:04:29.760","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-73252","references":[{"url":"https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e","label":"security-advisories@github.com"},{"url":"https://github.com/cesanta/mongoose/releases/tag/7.23","label":"security-advisories@github.com"},{"url":"https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3","label":"security-advisories@github.com"},{"url":"https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.00376,"epssPercentile":0.31425,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-14T19:41:34.958467Z"},"ingestedAt":"2026-10-14T19:49:57.615Z","slug":"CVE-2026-73252","body":"## Overview\n\nMongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS stack selected by MG_TLS_BUILTIN in src/tls_builtin.c accepts a TLS 1.3 record whose decrypted size is exactly the 16-byte authentication tag with no plaintext or ContentType byte. In mg_tls_recv_record(), the msgsz length check permits that record and the recv_len calculation underflows to SIZE_MAX, so a later handshake step treats stale buffer contents as a trusted message with an effectively unbounded length. An unauthenticated malicious TLS peer can trigger a heap out-of-bounds read before certificate or Finished validation, causing a remote denial of service. This issue is fixed in version 7.23.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":221893,"id":"CVE-2026-73252","ts":1792035897525,"field":"exploit_available","old":"false","new":"true"}]}