SB2026063037 - Reachable assertion in nats-server

CSH
CYBERSECURITY HELP
Sign In REGISTER

Main Vulnerability Database SB2026063037

SB2026063037 - Reachable assertion in nats-server

Published: June 30, 2026

Security Bulletin ID SB2026063037
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Reachable assertion (CVE-ID: N/A)

CWE-ID: CWE-617 - Reachable Assertion

CVSSv4: 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:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to reachable assertion in JWT claim processing in operator-mode authentication when processing a malformed client JWT issuer key. A remote attacker can send a specially crafted JWT containing a truncated public account key to cause a denial of service.

Only operator-mode deployments using JWT authentication are vulnerable, and the issue can be triggered before authentication completes.


Remediation

Install update from vendor's website.

References