CVE-2026-55098 Basekick-Labs CVE debrief

Who should care

Defenders and administrators of Arc deployments should assess exposure and implement compensating controls to prevent unauthorized access to sensitive data. They should verify exposure, implement compensating controls, and prioritize monitoring for suspicious activity. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and planning vendor-supported updates or mitigations through a

Why it matters

CVE-2026-55098 allows any authenticated token to read or enumerate every other database's data within the deployment, defeating RBAC. Defenders should verify exposure, implement compensating controls, and prioritize monitoring for suspicious activity.

• Defenders must verify exposure and implement compensating controls to prevent unauthorized access to sensitive data.
• The vulnerability allows any authenticated token to read or enumerate every other database's data within the deployment, defeating RBAC.
• Defenders should prioritize monitoring for suspicious activity and restricting access to sensitive data.

Technical summary

The fix for CVE-2026-47735 is incomplete, allowing any authenticated token to read or enumerate every other database's data within the deployment, defeating RBAC. The sandbox scope is the whole storage root, not the tenant, and the SQL denylist misses other DuckDB I/O family functions. This allows unauthorized access to sensitive data. The vulnerability was verified at HEAD `c08b892` (`v26.06.1-36`, includes 26.06.2). The root cause includes three composing gaps: the sandbox scope is the whole storage root, not the tenant; the SQL denylist still misses the rest of the DuckDB I/O family; and the original advisory enumerated functions are not fully blocked.

Defensive priority

Defenders should prioritize verifying exposure and implementing compensating controls, as the vulnerability allows any authenticated token to read or enumerate every other database's data within the deployment, defeating RBAC.

Recommended defensive actions

• Verify exposure by checking if the storage root is allowlisted and if the SQL denylist is missing other DuckDB I/O family functions.
• Implement compensating controls, such as restricting access to sensitive data and monitoring for suspicious activity.
• Apply the fix from commit 5dc8f53b70a3871b16b0cebf328f07c578af7a45 or later.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• 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 source corpus provides details on the vulnerability, including the incomplete fix for CVE-2026-47735, the allowlisted multi-tenant storage root, and the missed DuckDB I/O family functions. However, the corpus does not provide information on exploitation or specific victims.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.