7.3
HIGH
CVSS 3.1
CVE-2026-9086
Keycloak: keycloak: cross-site scripting (xss) via case-insensitive uri validation bypass
Overview
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.
Details
INFO
Published Date :
June 25, 2026, 5:17 p.m.
Last Modified :
July 15, 2026, 1:17 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c |
Solution
Update Keycloak to fix client URI validation bypass leading to XSS.
- Update Keycloak to the latest version.
- Apply relevant security patches.
- Review client registration configurations.
- Monitor for suspicious client registrations.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-9086.
| URL | Resource |
|---|---|
| https://access.redhat.com/errata/RHSA-2026:30049 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30050 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30083 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30084 | Third Party Advisory |
| https://access.redhat.com/security/cve/CVE-2026-9086 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2480170 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30049 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30050 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30083 | Third Party Advisory |
| https://access.redhat.com/errata/RHSA-2026:30084 | Third Party Advisory |
| https://access.redhat.com/security/cve/CVE-2026-9086 | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2480170 | Third Party Advisory |
| https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.json | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-9086 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-9086
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-9086 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-9086 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jul. 15, 2026
Action Type Old Value New Value Changed Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4.13', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'defaultStatus': 'affected'}] [{'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4.13-1', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4-19', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4-19', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4.13', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] -
Initial Analysis by [email protected]
Jul. 01, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:* versions from (including) 26.6 up to (excluding) 26.6.4 *cpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:* versions from (including) 26.4 up to (excluding) 26.4.13 Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:30049 Types: Third Party Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:30050 Types: Third Party Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:30083 Types: Third Party Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:30084 Types: Third Party Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2026-9086 Types: Third Party Advisory Added Reference Type Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2480170 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30049 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30050 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30083 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/errata/RHSA-2026:30084 Types: Third Party Advisory Added Reference Type redhat-SADP: https://access.redhat.com/security/cve/CVE-2026-9086 Types: Third Party Advisory Added Reference Type redhat-SADP: https://bugzilla.redhat.com/show_bug.cgi?id=2480170 Types: Third Party Advisory Added Reference Type redhat-SADP: https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.json Types: Third Party Advisory -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4.13', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'defaultStatus': 'affected'}] Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Added CWE CWE-79 Added Reference https://access.redhat.com/errata/RHSA-2026:30049 Added Reference https://access.redhat.com/errata/RHSA-2026:30050 Added Reference https://access.redhat.com/errata/RHSA-2026:30083 Added Reference https://access.redhat.com/errata/RHSA-2026:30084 Added Reference https://access.redhat.com/security/cve/CVE-2026-9086 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2480170 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9086.json -
CVE Modified by [email protected]
Jun. 26, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:30049 Added Reference https://access.redhat.com/errata/RHSA-2026:30050 Changed Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] [{'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4.13-1', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4-19', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4', 'versions': [{'status': 'unaffected', 'version': '26.4-19', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.4::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.4.13', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] -
CVE Modified by [email protected]
Jun. 25, 2026
Action Type Old Value New Value Changed Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'keycloak-rhel9-container', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'keycloak-rhel9-operator-container', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] [{'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-rhel9-operator', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] -
CVE Modified by [email protected]
Jun. 25, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:30083 Added Reference https://access.redhat.com/errata/RHSA-2026:30084 Changed Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:'], 'vendor': 'Red Hat', 'product': 'Red Hat Build of Keycloak', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] [{'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'keycloak-rhel9-container', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6-8', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'keycloak-rhel9-operator-container', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6', 'versions': [{'status': 'unaffected', 'version': '26.6.4-2', 'lessThan': '*', 'versionType': 'rpm'}], 'packageName': 'rhbk/keycloak-operator-bundle', 'collectionURL': 'https://catalog.redhat.com/software/containers/', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:build_keycloak:26.6::el9'], 'vendor': 'Red Hat', 'product': 'Red Hat build of Keycloak 26.6.4', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 25, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-9086', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-25T17:59:48.293762Z'} -
New CVE Received by [email protected]
Jun. 25, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/a:redhat:build_keycloak:'], 'vendor': 'Red Hat', 'product': 'Red Hat Build of Keycloak', 'packageName': 'rhbk/keycloak-rhel9', 'collectionURL': 'https://access.redhat.com/downloads/content/package-browser/', 'defaultStatus': 'affected'}] Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Added CWE CWE-79 Added Reference https://access.redhat.com/security/cve/CVE-2026-9086 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2480170
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.