How severe is CVE-2026-9086?

CVE-2026-9086 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-9086 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-9086?

CVE-2026-9086 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-9086?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-9086 have an EU (EUVD) identifier?

Yes. CVE-2026-9086 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39473.

When was CVE-2026-9086 published?

CVE-2026-9086 was published on 2026-06-25 and last updated on 2026-07-01.

CVE-2026-9086

CVE-2026-9086 is a high-severity vulnerability in Redhat Build Of Keycloak with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: High (CVSS 3.x base score 7.3)
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39473
Weakness: CWE-79
Affected product: Redhat Build Of Keycloak
Published: 2026-06-25
Last modified: 2026-07-01

Description

A flaw was found in Keycloak. A remote attacker with administrative privileges, specifically those with `manage-client` permission or access to client registration endpoints, could bypass client Uniform Resource Identifier (URI) validation. This is achieved by registering a malicious client with a specially crafted redirect URI using a case-insensitive `javascript:` or `data:` scheme. This Cross-Site Scripting (XSS) vulnerability allows for arbitrary code execution in the Keycloak origin when a victim clicks the crafted link, such as in the logout flow or the Admin Console.

Frequently asked questions

What is CVE-2026-9086?: A flaw was found in Keycloak. A remote attacker with administrative privileges, specifically those with `manage-client` permission or access to client registration endpoints, could bypass client Uniform Resource Identifier (URI) validation. This is achieved by registering a malicious client with a specially crafted redirect URI using a case-insensitive `javascript:` or `data:` scheme. This Cross-Site Scripting (XSS) vulnerability allows for arbitrary code execution in the Keycloak origin when a victim clicks the crafted link, such as in the logout flow or the Admin Console.
How severe is CVE-2026-9086?: CVE-2026-9086 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-9086 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-9086?: CVE-2026-9086 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-9086?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-9086 have an EU (EUVD) identifier?: Yes. CVE-2026-9086 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39473.
When was CVE-2026-9086 published?: CVE-2026-9086 was published on 2026-06-25 and last updated on 2026-07-01.

References

Affected products (1)

cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*

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