Cross-instance user impersonation through image renderer JWTs

published 2026-11-11 19h ago modified 2026-11-11 19h ago also EUVD-2026-123545

cvss: 7.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: —; no EPSS score yet
public exploits: 0; none known

When independent Grafana instances share the same [rendering] renderer_token, an image renderer key issued by one instance is accepted by the others, so a user on one instance could act as the user with the same ID on another (origin validation error). This affects instances with the renderAuthJWT feature toggle enabled, the default from Grafana 13.0.0.

Is CVE-2026-102589 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.1	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

Affected products

Grafana Grafana OSS
Grafana Grafana Enterprise

Classification

Weakness

CWE-346 Origin Validation Error
CWE-863 Incorrect Authorization
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

grafana.com /security/security-advisories/cve-2026-102589
vendor-advisory

Sources

CVE List CVE-2026-102589
NVD CVE-2026-102589

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.