CVE-2026-58254: medium-severity vulnerability in nats-io nats-server
NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.3%
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
Affected products
nats-io · nats-serverRelated CVEs — nats-io nats-server
In the same product, most dangerous first.
CVE-2026-58210HIGHNATS Server: MQTT partial CONNECT packets can exhaust pre-auth memoryEPSS 0.7%CVE-2026-58250HIGHNATS Server: Pre-auth server crash via double INFO in leafnode handshakeEPSS 0.7%CVE-2026-29785HIGHNATS Server panic via malicious compression on leafnode portEPSS 0.7%CVE-2026-33218HIGHNATS has pre-auth server panic via leafnode handlingEPSS 0.6%CVE-2025-30215CRITICALNATS-Server Fails to Authorize Certain Jetstream Admin APIsEPSS 0.6%CVE-2026-58208MEDIUMNATS Server: MQTT-over-WebSocket Path Can Crash WebSocket-Only JetStream Servers Before MQTT Is EnabledEPSS 0.6%