NULL pointer dereference in nats-server - #VU135936
Published: June 30, 2026
Vulnerability identifier: #VU135936
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: N/A
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: NATS - The Cloud Native Messaging System
Affected software:
nats-server
nats-server
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a null pointer dereference in the leafnode handshake logic when processing repeated leafnode INFO protocol messages before authentication and account setup complete. A remote attacker can send repeated INFO messages to cause a denial of service.
Only leafnode listeners with compression enabled are vulnerable.
Remediation
Install security update from vendor's website.