# CVE-2026-93475: NetX Secure X.509 parser out-of-bounds write in RSA signature verification

Source: https://junglewise.ai/threats/cve-2026-93475-the-x-509-parser-in-netx-secure-accepts-an-rsa-public-key-of-any  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-20. Updated: 2026-10-20  
License: CC BY 4.0 with a link back

CVE-2026-93475 · Severity: info · Published 2026-10-20

NetX Secure is a TLS/DTLS library used to verify certificates in embedded systems. An attacker can send a malicious certificate with an oversized RSA key to trigger an out-of-bounds memory write during signature verification, potentially corrupting memory and gaining control of the system. This occurs before authentication, requiring no credentials.

Technologies: [Eclipse ThreadX NetX Secure](https://junglewise.ai/threats/technologies/eclipse-threadx-netx-secure). Vendors: [Eclipse ThreadX](https://junglewise.ai/threats/vendors/eclipse-threadx).

## Quick answers

**Is CVE-2026-93475 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-93475 being exploited in the wild.

**How severe is CVE-2026-93475?** Informational severity, published 20 October 2026.

**Which products and versions are affected?** Eclipse ThreadX NetX Secure <= 6.5.1.202602.

**Is there a fix for CVE-2026-93475?** Yes: fixed in 6.5.2.202603. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-93475 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-93475?** Check whether you run Eclipse ThreadX NetX Secure at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 6.5.2.202603

## Technical details

The X.509 parser accepts RSA public keys of any size (up to 65535 bytes) but decrypts signatures into a fixed 512-byte buffer dimensioned for 4096-bit keys. The verification path fails to validate key size at multiple points: during parsing, during RSA initialization, and during the decryption operation. An attacker supplies an oversized key in their own certificate chain (checked before the trusted store), causing the modular exponentiation result to overflow the buffer and overwrite adjacent static variables.

## Affected products

- Eclipse ThreadX NetX Secure <= 6.5.1.202602

## Timeline

- 2026-10-20: disclosed
- 2026-10-02: patched: GHSA advisory published

## References

- [https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-rcv5-vfff-25gh](https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-rcv5-vfff-25gh)

## Related threats

- [NetX Secure memory corruption in NX_SECURE_KEY_CLEAR](https://junglewise.ai/threats/cve-2026-102760-when-netx-secure-is-built-with-nx-secure-key-clear-every-tls)
- [Eclipse ThreadX NetX Secure DTLS cookie prediction](https://junglewise.ai/threats/cve-2026-102719-predictable-dtls-helloverifyrequest-cookie-in-netx-secure)