CVE-2026-58254CWE-863

NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check

Medium · published July 8, 2026

CVSS v4.0
5.3
EPSS
0%
Percentile
22.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
5.3 · MEDIUM
Vector
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
EPSS
0.00308 · 22.4th percentile
Weakness
CWE-863 · Incorrect Authorization
Published
2026-07-08T19:56Z
EPSS history
Timeline
  • 08 JUL 19:56Z
    NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check
    cvelistv5