# CVE-2026-92853: NetX Secure TLS 1.3 out-of-bounds read in Certificate parser

Source: https://junglewise.ai/threats/cve-2026-92853-the-tls-1-3-certificate-message-parser-in-netx-secure-decrements  
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-2026-92853 · Severity: info · Published 2026-10-20

NetX Secure is a TLS/DTLS library embedded in IoT and embedded systems. A flaw in its TLS 1.3 Certificate message parser allows an unauthenticated attacker to send a malformed zero-length certificate message that causes the parser to read memory far beyond the packet buffer, crashing the application and denying service to the entire firmware image.

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

## Quick answers

**Is CVE-2026-92853 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-92853 being exploited in the wild.

**How severe is CVE-2026-92853?** Informational severity, published 20 October 2026.

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

**Is there a fix for CVE-2026-92853?** Yes: fixed in NetX Duo 6.5.2.202603. Until then: Build without TLS 1.3 support to remove the affected code path, though this eliminates TLS 1.3 capability entirely. Within a TLS 1.3-enabled build, no workaround exists prior to upgrade.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-20","note":"CVE-2026-92853 published on NVD"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-92853 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-92853?** Check whether you run Eclipse ThreadX NetX Duo 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 NetX Duo 6.5.2.202603

Build without TLS 1.3 support to remove the affected code path, though this eliminates TLS 1.3 capability entirely. Within a TLS 1.3-enabled build, no workaround exists prior to upgrade.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-20","note":"CVE-2026-92853 published on NVD"}]

## Technical details

The TLS 1.3 Certificate-message parser decrements message length to skip a context byte without checking that the message has a byte available, causing unsigned integer underflow. A zero-length Certificate message wraps the unsigned length to 0xFFFFFFFF, bypassing all subsequent bounds checks and causing the parser to read past the session packet buffer. The attack requires only a four-byte handshake header with no cryptographic validity and is reachable pre-authentication.

## Affected products

- Eclipse ThreadX NetX Duo <= 6.5.1.202602

## References

- [https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-893m-9g4r-4992](https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-893m-9g4r-4992)

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