CVE-2021-26529: Cesanta Mongoose

Critical severity, CVSS 9.1. EPSS: 1.5% chance of exploitation in the next 30 days.

The mg_tls_init function in Cesanta Mongoose HTTPS server 7.0 and 6.7-6.18 (compiled with mbedTLS support) is vulnerable to remote OOB write attack via connection request after exhausting memory pool.

Affected products

• Cesanta Mongoose: from 6.7, up to and including 6.18; version 7.0 only

Published 2021-02-08. Last modified 2026-06-17.