CVE-2026-73252

The Mongoose embedded web server and network library (prior to version 7.23 ) contains an unauthenticated remote heap out-of-bounds read vulnerability in its built-in TLS stack. The root cause is an off-by-one length check in mg_tls_recv_record() within src/tls_builtin.c, which allows a TLS 1.3 r...

CVE-2026-73252 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

Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TLS stack selected by MGTLSBUILTIN in src/tlsbuiltin.c accepts a TLS 1.3 record whose decrypted size is exactly the 16-byte authentication tag with no plaintext or ContentType byte. In mgtlsrecvrecord, the msgsz...