Intel

AIKIDO-2026-982000

cesanta.mongoose is vulnerable to Out-of-bounds Read

Out-of-bounds ReadCVE-2026-73252 Published Aug 13, 2026

75

High Risk

This Affects:

C++cesanta.mongoose
7.13 - 7.22
Fixed in 7.23
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TL;DR

The built-in TLS stack accepts a record whose decrypted size equals the AEAD tag size, leaving no room for the required content-type byte. The remaining-length computation then underflows to a maximum value that persists, causing later handshake steps to treat stale buffer bytes as a trusted, effectively unbounded message. An unauthenticated peer can trigger an attacker-influenced heap over-read and crash the service before authentication. The fix requires records to exceed the tag size.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and you use the built-in TLS backend (MG_TLS_BUILTIN).

Background info

cesanta.mongoose is vulnerable to Out-of-bounds Read in versions 7.13 - 7.22.

How to fix this

Upgrade the cesanta.mongoose library to the patch version.