CVE-2026-33219

MEDIUM EPSS 26.2%
Published Mar 25, 20263mo ago · Modified Jun 17, 20262w ago
5.3 CVSS 3.1
Medium
Find Similar
Published Mar 25, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment.

CVSS Details

Base Score
5.3
Exploitability
3.9
Impact
1.4
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability Low

Threat Intelligence

EPSS Exploit Probability
26.2% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-770

Affected Products 2

VendorProductVersionRange
linuxfoundationnats-server* <2.11.15
linuxfoundationnats-server*≥2.12.0  –  <2.12.6

References 4

  • advisories.nats.io https://advisories.nats.io/CVE/secnote-2026-02.txt
    MitigationVendor Advisory
  • advisories.nats.io https://advisories.nats.io/CVE/secnote-2026-11.txt
    MitigationVendor Advisory
  • github.com https://github.com/advisories/GHSA-qrvq-68c2-7grw
    MitigationVendor Advisory
  • github.com https://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j
    MitigationVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.