Auth bypass in Linuxfoundation Nats-Server
CVE-2026-58251
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, an authenticated user with subscription deny permissions could bypass a plain subject deny rule by using a queue subscription, because queue-specific deny evaluation could override the plain subject deny result when the queue name itself was not denied. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (38.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Linuxfoundation Nats-Server
- Nats-Io Nats-Server — versions < 2.11.16, >= 2.12.0-RC.1, < 2.12.7
Weakness classification (CWE)
References
- github.com/nats-io/nats-server/security/advisories/GHSA-jx8g-9g95-6322 (Vendor Advisory)
- github.com/nats-io/nats-server/commit/013586288078def45a6788096924eb4d150db65c (Patch)
- github.com/nats-io/nats-server/commit/79c2f6e9ff87f594596337b6427dda85c38d1fe1 (Patch)
- github.com/nats-io/nats-server/commit/b9ffb63b85e7db3d25a13b2e234f5f7f7c13164d (Patch)
- github.com/nats-io/nats-server/releases/tag/v2.11.16 (Release Notes)
- github.com/nats-io/nats-server/releases/tag/v2.12.7 (Release Notes)
- github.com/nats-io/nats-server/releases/tag/v2.14.0 (Release Notes)
Frequently asked questions
- What is CVE-2026-58251?
- CVE-2026-58251 is a medium-severity vulnerability in Linuxfoundation Nats-Server, classified under Improper Authorization. CVSS score: 6.5/10. Published 2026-07-08.
- How severe is CVE-2026-58251?
- Medium severity. CVSS v3 base score is 6.5 out of 10.