Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely different organization could gain access to the Keycloak realm, potentially accessing sensitive data or performing unauthorized actions.
CVE-2026-18215
MEDIUMPre-NVD 6.86.8—Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
Score 6.8 from GitHub Security Advisory published 2026-07-31. a secondary CVSS source baseline 6.8; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
6.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 6.8Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.8
- EG Score
- 6.8(high)
- EG Risk
- 31(Track)EG Risk 31/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity68% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
July 31, 2026
Last Modified
July 31, 2026
Advisory Details (2)
Auto-updated Jul 31, 2026Patch available. Sources: redhat.
redhat
2508309 – (CVE-2026-18215) CVE-2026-18215 keycloak-services: keycloak-services: Microsoft external access-token exchange bypasses configured tenant
https://bugzilla.redhat.com/show_bug.cgi?id=2508309Vendor Advisories for CVE-2026-18215(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 7× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-31 11:26 UTCEG score recompute
- 2026-07-31 11:26 UTCGHSA enrichment
- 2026-07-31 11:15 UTCEG score recompute
- 2026-07-31 11:15 UTCGHSA enrichment
- 2026-07-31 08:18 UTCEG score recompute
- 2026-07-31 07:28 UTCEG score recompute
- 2026-07-31 07:28 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-287
Frequently asked(4)
What is CVE-2026-18215?
CVE-2026-18215 is a medium vulnerability published on July 31, 2026. Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely…
When was CVE-2026-18215 disclosed?
CVE-2026-18215 was first published in the National Vulnerability Database on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-18215?
CVE-2026-18215 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2026-18215?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18215, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-18215
Is Your Infrastructure Affected by CVE-2026-18215?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.