CVE-2026-93475 Out-of-bounds Write via an Unbounded RSA Modulus in NetX Secure X.509
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-93475?
CVE-2026-93475 is a critical vulnerability in Eclipse ThreadX - NetX Duo, published on 20 Oct 2026.
Official description
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.
Which versions are affected by CVE-2026-93475?
How do I fix CVE-2026-93475?
No fix has been published for CVE-2026-93475 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-93475 being exploited?
There is no known exploitation of CVE-2026-93475 in the wild and no public exploit code.
Sources
Also known as GHSA-rcv5-vfff-25gh.