CVEvulnerability

CVE-2026-33219

5.3 MEDIUM Published 2026-03-25 Modified 2026-09-09 Official page ↗
Status
Modified
Published
2026-03-25
Last modified
2026-09-09
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-770

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.

Affected configurations

• linuxfoundation nats-server (< 2.11.15) • linuxfoundation nats-server (>= 2.12.0 < 2.12.6)

Related

Weakness · CWE (1)

  • CWE-770 Allocation of Resources Without Limits or Throttling weakness

References