# CVE-2026-102719: NetX Secure DTLS server issues predictable HelloVerifyRequest cookies, so a spoofed client can pass the return-routability check

Status: published. Published: 2026-09-29. Updated: 2026-11-04.

In Eclipse ThreadX NetX Duo versions 6.0 through 6.5.2.202603a, the NetX Secure DTLS server fills HelloVerifyRequest cookies from NX_RAND(), by default the C library rand(), with no key and no binding to the client. An attacker who can predict the generator's output can pass the cookie exchange from a spoofed address and make the server send its handshake flight to a victim, using it as a traffic reflector.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Eclipse Foundation / Eclipse ThreadX NetX Duo: ≥ 6.0; ≤ 6.5.2.202603a (affected, custom); 6.5.2.202603b (unaffected, custom). Source: CNA: eclipse

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L; source: CNA: eclipse

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: emo@eclipse.org

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-03; percentile 10.89%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-338

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-j6gx-3j6v-3hm4 (CNA: eclipse)

- https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-j6gx-3j6v-3hm4 (emo@eclipse.org)

## Provenance

- CNA: eclipse: https://www.cve.org/CVERecord?id=CVE-2026-102719; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102719; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-102719; retrieved 2026-11-04; source updated Not reported

Revision: cf35395b18ad52c641f225f551ac61871ae2eb5b47a9cea9e3034e5b533c95ff

Canonical: https://y2.dev/cve/CVE-2026-102719

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