NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead (nats-io nats-server)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.59 % · percentile 48 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server. This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack.
Weaknesses (CWE)
- CWE-190 — Integer Overflow or Wraparound
- CWE-1286 — Improper Validation of Syntactic Correctness of Input
References
- https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6
- https://advisories.nats.io/CVE/secnote-2026-03.txt
- https://access.redhat.com/security/cve/CVE-2026-27889
- https://bugzilla.redhat.com/show_bug.cgi?id=2451447
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27889.json
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/errata/RHSA-2026:21769
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-pq2q-rcw4-3hr6 — NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead
- GO-2026-4841 — NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead in github.com/nats-io/nats-server
European references
- ENISA EUVD · EUVD-2026-15962
- GCVE · GCVE-0-2026-27889
Affected configurations (NVD CPE)
cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*≥ 2.2.0 < 2.11.14cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*≥ 2.12.0 < 2.12.5
Affected products
| Product | Versions |
|---|---|
| nats-io · nats-server | affected >= 2.2.0, < 2.11.14 ; affected >= 2.12.0, < 2.12.5 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |