CVE-2026-33218GHSA-VPRV-35VV-Q339BIT-NATS-2026-33218GO-2026-4837
NATS has pre-auth server panic via leafnode handling
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 2.12.6, 2.11.15
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
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 client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- nats-io nats-server
From 2.12.0-RC.1 · fixed in 2.12.6
- github.com/nats-io/nats-server/v2Go
fixed in 2.11.15
- github.com/nats-io/nats-server/v2Go
From 2.12.0-RC.1 · fixed in 2.12.6
- github.com/nats-io/nats-serverGo
All versions
- github.com/nats-io/nats-server/v2Go
fixed in 2.11.15; From 2.12.0-RC.1 · fixed in 2.12.6