Resource exhaustion in nats-server - #VU166200
Published: November 13, 2026
Vulnerability identifier: #VU166200
CSH Severity: Low
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service through excessive memory consumption.
The vulnerability exists due to uncontrolled resource consumption in JetStream backup format detection when processing incoming compressed stream backups. A remote user can submit a crafted backup using stream-restore permissions to cause incoming data to accumulate without a finite buffer limit while format detection waits for recognizable output, exhausting memory and disrupting the server process.
Account stream-storage limits do not bound the temporary format-detection buffer.
Affected software
nats-server
Remediation
Install security update from vendor's website.
nats-server - update to 2.15.1