Eclipse NetX Duo: Out-of-bounds read in TLS 1.3 Certificate parsing
Summary
A missing bounds check in the TLS 1.3 Certificate message parser of NetX Secure, part of Eclipse NetX Duo, allows a malicious TLS 1.3 server to trigger an integer underflow and a heap out-of-bounds read. The read data is passed to the certificate parser, and an out-of-bounds write is possible but not confirmed. The attack requires no credentials and occurs during the handshake, before certificate verification, so a rogue server, an on-path attacker or a rogue access point can trigger it. The flaw affects embedded devices that run NetX Secure with TLS 1.3 enabled.
Affected
- Eclipse ThreadX NetX Duo 6.5.1.202602 and earlier (CNA record: 0 to <= 6.5.1.202602)
- Only builds with NX_SECURE_TLS_TLS_1_3_ENABLED defined, on the client and the server side
- Vendor firmware that embeds NetX Duo may use its own version numbers: Unknown.
Fixed in
- Fixed in NetX Duo 6.5.2.202603
- Security hotfix 6.5.2.202603a is the newest release; whether it also contains the fix for this CVE is not confirmed in the excerpts reviewed.
Workaround
- The CVE record and advisory list no workaround for TLS 1.3 builds.
- Building without TLS 1.3 (NX_SECURE_TLS_ENABLE_TLS_1_3 not set) removes the affected code path.
- Whether a device uses TLS 1.3 is unknown until the build configuration is checked.
Exploitation
- No public exploit known.
- Not listed in the CISA KEV catalog.
- CISA SSVC: exploitation none, automatable yes, technical impact partial.
- EPSS about 0.3% (Vulners).
- No known exploitation in the wild.
Our recommendation
- Inventory devices that run ThreadX or NetX Duo, including third-party firmware.
- Ask device vendors for firmware based on 6.5.2.202603a or later, or at least 6.5.2.202603.
- Check whether TLS 1.3 is enabled on devices that do not need it, and disable it where possible.
- Restrict outbound connections from devices to trusted endpoints.
- Monitor for vendor firmware updates and read the GitHub advisory for the authoritative version range.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- GitHub Security Advisory GHSA-4m85-f9qh-q3jv github.com
- NetX Duo release v6.5.2.202603_rel github.com
- Eclipse ThreadX security hotfix discussion github.com
- OpenCVE entry CVE-2026-92843 app.opencve.io
- VulDB entry 422846 vuldb.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 01:28.
Original description (NVD)
A missing bounds check in the TLS 1.3 Certificate-message parser of NetX Secure lets a malicious TLS 1.3 server trigger an unsigned-integer underflow and a subsequent heap out-of-bounds read in any peer that processes a remote Certificate message. It is reachable pre-authentication, during the normal handshake, before certificate verification completes.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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