CVE-2026-58254: NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.8, message trace destination checks were applied to ordinary client connections but not consistently to messages arriving through leafnode connections, allowing a leafnode operator to send trace events to subjects that would not otherwise be permitted and to use trace-only behavior to prevent normal delivery or storage of affected messages. This issue is fixed in versions 2.14.3 and 2.12.8.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nats-serverto a version that resolves this vulnerability.Fixed in 2.14.3 - Upgrade
Upgrade
nats-serverto a version that resolves this vulnerability.Fixed in 2.12.8
Event History
Frequently Asked Questions
What is the severity of CVE-2026-58254?
CVE-2026-58254 has a medium severity rating of 5.3.
How do I fix CVE-2026-58254?
To fix CVE-2026-58254, upgrade to NATS Server version 2.14.3 or 2.12.8 and ensure the Leaf node connection checks are applied correctly.
What components are affected by CVE-2026-58254?
CVE-2026-58254 affects NATS Server versions prior to 2.14.3 and 2.12.8.
What type of vulnerability is CVE-2026-58254?
CVE-2026-58254 is a permission check bypass vulnerability related to leaf node connections.
Are messages sent through leaf node connections impacted by CVE-2026-58254?
Yes, messages arriving through leaf node connections can bypass Nats-Trace-Dest permission checks due to CVE-2026-58254.