CVE-2026-63087: Missing Auth (CVSS 9.8)

Description

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0043

Probability of exploitation

0.35%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-306 Missing Authentication

References

Other References

https://github.com/geo-chen/oss/blob/main/oncall.md https://www.vulncheck.com/advisories/grafana-oncall-unauthenticated-token-hijack-via-plugin-install-endpoint

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-63087? +

CVE-2026-63087 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0043, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-63087? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-63087