CVE-2026-93475

The X.509 parser in NetX Secure accepts an RSA public key of any size, but every signature-verification path decrypts into fixed-size buffers dimensioned for the `NX_CRYPTO_MAX_RSA_MODULUS_SIZE` default of 4096 bits. A certificate carrying a larger modulus drives an out-of-bounds write past a file-scope static during ordinary certificate-chain verification. It is reachable pre-authentication. The issuer used for the crypto operation is looked up in the remote, peer-supplied store before the trusted store, so the attacker supplies the oversized key themselves as an intermediate in the chain they present. It triggers on a TLS or DTLS client verifying a malicious server's chain, and on a server performing client-certificate authentication.

Score

CVSS 4.0 9.3 Critical

Status

Awaiting Analysis - emo@eclipse.org

Published

2026-10-20

Last modified

2026-10-20

Weaknesses

CWE-1284, CWE-787

Affected products

• Eclipse Threadx - Netx Duo (Eclipse Foundation)

References

• https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-rcv5-vfff-25gh