7.5
High
CVE-2026-73252 Mongoose is an embedded web server and network library
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.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Mongoose 7.23 | earliest → < 7.23 | 7.23 |
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The 38 CVEs of Mongoose →
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CVE-2026-63626
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CVE-2026-73261
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CVE-2026-73260
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7.5
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