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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.007 (53.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Grafana-Cold-Storage Oncall — versions 0
Weakness classification (CWE)
References
- github.com/geo-chen/oss/blob/main/oncall.md (technical-description, exploit)
- www.vulncheck.com/advisories/grafana-oncall-unauthenticated-token-hijack-via-pl… (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.