CVE-2026-107889
Keycloak-services: keycloak-services: stored xss on login page via kcsanitize bypass
Description
A flaw was found in the login theme rendering component of Keycloak. The issue occurs because the security filter responsible for cleaning user input can be bypassed, allowing a realm administrator to store malicious scripts in display fields. This could result in unauthorized JavaScript execution in the browsers of users visiting the login page, potentially leading to data exposure or session interference.
INFO
Published Date :
Oct. 9, 2026, 5:16 a.m.
Last Modified :
Oct. 9, 2026, 5:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-107889
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Apply the latest Keycloak update.
- Review and sanitize all user-supplied input.
- Implement input validation on display fields.
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-2026-107889.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-107889 | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2548355 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-107889 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-2026-107889
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-2026-107889 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-107889 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.
-
New CVE Received by [email protected]
Oct. 09, 2026
Action Type Old Value New Value Added Description A flaw was found in the login theme rendering component of Keycloak. The issue occurs because the security filter responsible for cleaning user input can be bypassed, allowing a realm administrator to store malicious scripts in display fields. This could result in unauthorized JavaScript execution in the browsers of users visiting the login page, potentially leading to data exposure or session interference. Added CVSS V3.1 AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/107xxx/CVE-2026-107889.json">CVE-2026-107889</a> Added Reference https://access.redhat.com/security/cve/CVE-2026-107889 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2548355