Improper Certificate Validation in nats-server - #VU166199
Published: November 13, 2026
Vulnerability identifier: #VU166199
CSH Severity: Medium
CVSS v4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass TLS certificate revocation checks, potentially compromising the confidentiality and integrity of connections.
The vulnerability exists due to improper certificate validation in the NATS Server OCSP validation component when checking certificate revocation status. A remote attacker can supply a valid OCSP response for another certificate from the same issuer to have a revoked certificate accepted by the affected revocation check.
Affected software
nats-server
Remediation
Install security update from vendor's website.
nats-server - addressed in versions 2.14.9, 2.15.2