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 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.
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Fri, 23 Oct 2026 00:45:00 +0000
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| Description | 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 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. | |
| Title | Mongoose: Unauthenticated remote heap out-of-bounds read in built-in TLS: off-by-one length check in mg_tls_recv_record() underflows recv_len to SIZE_MAX | |
| Weaknesses | CWE-125 CWE-191 |
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cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-10-14T18:24:16.659Z
Updated: 2026-10-14T19:41:57.801Z
Reserved: 2026-08-11T17:18:01.598Z
Link: CVE-2026-73252
Updated: 2026-10-14T19:41:54.563Z
Status : Deferred
Published: 2026-10-14T19:17:19.667
Modified: 2026-10-16T20:04:29.760
Link: CVE-2026-73252
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