CVE-2026-58253
Prior to 2.14.0, 2.12.7, and 2.11.16, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L
- EPSS
- 0.37% probability · 30th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- linuxfoundation/nats-server
- Source
- security-advisories@github.com
References
- https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6Patch
- https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6Patch
- https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3Patch
- https://github.com/nats-io/nats-server/releases/tag/v2.11.16Release Notes
- https://github.com/nats-io/nats-server/releases/tag/v2.12.7Release Notes
- https://github.com/nats-io/nats-server/releases/tag/v2.14.0Release Notes
- https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.