CVE-2026-102719
NetX Secure DTLS server issues predictable HelloVerifyRequest cookies, so a spoofed client can pass the return-routability check
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
NetX Secure DTLS server issues predictable HelloVerifyRequest cookies, so a spoofed client can pass the return-routability check
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.
- Record
CVE-2026-102719- 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 - Weakness
- CWE-338
- Updated
- 2026-11-04
EUVDEUVD-2026-89182
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.
- Record
EUVD-2026-89182- 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 - Updated
- 2026-11-04
GitHub AdvisoriesGHSA-3fp7-fjmc-gqr7
Predictable DTLS HelloVerifyRequest Cookie in NetX Secure
Predictable DTLS HelloVerifyRequest Cookie in NetX Secure
- Record
GHSA-3fp7-fjmc-gqr7- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/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 - Weakness
- CWE-330, CWE-338
- Updated
- 2026-11-04
NVD
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.
- Record
CVE-2026-102719- 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 - Weakness
- CWE-338
- Updated
- 2026-11-04
OSV
NetX Secure DTLS server issues predictable HelloVerifyRequest cookies, so a spoofed client can pass the return-routability check
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.
- Record
CVE-2026-102719- 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 - Weakness
- CWE-338
- Updated
- 2026-11-07
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| products | EUVD | |
| cwes, description, facts, products, severity, title | CVE List | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-102719 is a medium vulnerability (CVSS 6.3) in Eclipse Foundation Threadx Netx Duo, published September 29, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 10th percentile. No source names a fixed version.