Auth bypass in Grafana-Cold-Storage Oncall
CVE-2026-63087
Grafana OnCall through 1.16.11 contains an unauthenticated access vulnerability that allows remote attackers to obtain a valid PluginAuthToken by sending a POST request to the internal plugin install endpoint using hardcoded default stack_id and org_id values present in the public source tree. Attackers can leverage the acquired token to authenticate against all internal API endpoints, create arbitrary Admin users via the user-context header bootstrap path, revoke the legitimate plugin token, and redirect OnCall-to-Grafana API calls to an attacker-controlled host by overwriting the organization's grafana_url and api_token.
Vulnerability class: Broken Authentication
EPSS: 0.006 (46.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Grafana-cold-storage Oncall — versions 0
Weakness classification (CWE)
References
- disclosure@vulncheck.com (technical-description, exploit)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63087?
- CVE-2026-63087 is a critical-severity vulnerability in Grafana-Cold-Storage Oncall, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-07-16.
- How severe is CVE-2026-63087?
- Critical severity. CVSS v3 base score is 9.8 out of 10.