How severe is CVE-2026-9086?

No CVSS score has been assigned to CVE-2026-9086 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-9086?

CVE-2026-9086 affects the following packages: keycloak (Bitnami). Ecosystems affected: Bitnami.

How do I fix CVE-2026-9086?

Update keycloak to 26.4.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-9086 is resolved across your whole dependency graph.

How do I detect CVE-2026-9086 in my Bitnami dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for keycloak, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-9086 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-9086 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-9086 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-9086?

CVE-2026-9086 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 56th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-9086?

CVE-2026-9086 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-9086 published, and has it been updated?

CVE-2026-9086 was published on August 25, 2026 and was last updated on September 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 Bitnami

Not in CISA KEV

CVE-2026-9086 — keycloak

CVE-2026-9086 is a Cross-site Scripting (XSS) vulnerability in keycloak. A fix is available for keycloak — see the affected versions and patch details below.

Keycloak: keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass

Published

Aug 25, 2026

Updated

Sep 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-9086.

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs56th percentile — riskier than 56% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

📦keycloak

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Bitnami packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦Bitnami	`keycloak`	≥ 26.4.0&&< 26.4.13	26.4.13

Affected Products

1 product · 2 configurations

Application

build of keycloakredhat

≥ 26.6 && < 26.6.4

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for keycloak, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update keycloak to 26.4.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-9086 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This flaw is rated as High. Keycloak's client URI validation is vulnerable to a case-insensitivity issue, allowing attackers to bypass scheme blocklists by using mixed-case `javascript:` or `data:` URIs. This can lead to cross-site scripting (XSS) in the Keycloak origin when a victim interacts with a crafted link,…

Workaround published by Red Hat

To mitigate this vulnerability, restrict the ability to register new clients and manage existing client configurations. If Dynamic Client Registration is not required, disable it in Keycloak's Realm Settings under Client Registration Policies. If Dynamic Client Registration is necessary, ensure that policies are strictly configured to prevent anonymous client registration and require initial access tokens for all client registrations. Additionally, limit the `manage-client` role to only trusted administrators. Changes to Keycloak configuration may require a service restart or redeployment to take effect.

Source: Red Hat security advisory for CVE-2026-9086 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat build of Keycloak 26.4	`rhbk/keycloak-operator-bundle:26.4.13-1`	RHSA-2026:30050
Red Hat build of Keycloak 26.4.13	`rhbk/keycloak-rhel9`	RHSA-2026:30049
Red Hat build of Keycloak 26.6	`rhbk/keycloak-operator-bundle:26.6.4-2`	RHSA-2026:30084
Red Hat build of Keycloak 26.6.4	`rhbk/keycloak-rhel9`	RHSA-2026:30083

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

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