CVE-2026-73252

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/cesanta/mongoose/commit/758e301f0c9a9885c1b716195df5fe6d6ac9d53e
https://github.com/cesanta/mongoose/releases/tag/7.23
https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3
https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3

Configurations

No configuration.

History

14 Oct 2026, 20:17

Type	Values Removed	Values Added
References	~~() https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3 -~~	() https://github.com/cesanta/mongoose/security/advisories/GHSA-hq58-98f5-2wg3 -

14 Oct 2026, 19:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-14 19:17

Updated : 2026-10-16 20:04

NVD link : CVE-2026-73252

Mitre link : CVE-2026-73252

CVE.ORG link : CVE-2026-73252

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

CWE-191

Integer Underflow (Wrap or Wraparound)

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