PatchSiren cyber security CVE debrief
CVE-2026-46562 yamcs CVE debrief
CVE-2026-46562 is a critical vulnerability in Yamcs' Nashorn ScriptEngine. Prior to version 5.12.7, the ScriptEngine was constructed without a ClassFilter, allowing users with ChangeMissionDatabase privilege to override algorithms and execute arbitrary OS commands as the Yamcs process. In default configurations, the built-in guest user has superuser=true, making the issue reachable without authentication. This vulnerability is fixed in versions 5.12.7 and 5.13.0, which disable algorithm editing by default.
- Vendor
- yamcs
- Product
- Unknown
- CVSS
- CRITICAL 9.8
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-16
- Original CVE updated
- 2026-07-16
- Advisory published
- 2026-07-16
- Advisory updated
- 2026-07-16
Who should care
Users of Yamcs versions prior to 5.12.7 or 5.13.0 should be aware of this critical vulnerability. Specifically, those with ChangeMissionDatabase privilege or using the default configuration with the built-in guest user should take immediate action to patch their systems.
Technical summary
The Nashorn ScriptEngine in Yamcs was constructed without a ClassFilter, allowing user-supplied JavaScript to access arbitrary Java classes. This could be exploited by a user with ChangeMissionDatabase privilege to execute arbitrary OS commands as the Yamcs process. The vulnerability is exacerbated by the default configuration, where the built-in guest user has superuser=true, making it reachable without authentication. The issue is addressed in versions 5.12.7 and 5.13.0 by disabling algorithm editing by default.
Defensive priority
High
Recommended defensive actions
- Immediately upgrade to Yamcs version 5.12.7 or 5.13.0
- Disable algorithm editing if not required
- Restrict ChangeMissionDatabase privilege to trusted users
- Monitor for suspicious algorithm changes
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
Evidence notes
The CVE record was published on 2026-07-16T17:16:56.953Z and last modified on 2026-07-16T19:16:47.040Z. The NVD entry is currently Undergoing Analysis. Multiple source references are provided, including commits and releases from the Yamcs GitHub repository.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-16T17:16:56.953Z and has not been modified since then. The NVD entry is currently Undergoing Analysis.