CVE-2026-9689
Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604
Description
A flaw was found in Keycloak, an open-source identity and access management solution. When a client application is configured to accept broad redirect Uniform Resource Identifiers (URIs), a remote attacker can manipulate the authentication process by crafting a special web address. If a user clicks this link, the client application might incorrectly prioritize attacker-controlled information over legitimate data. This vulnerability, known as HTTP parameter pollution, could allow an attacker to bypass security measures or gain unauthorized access to resources.
INFO
Published Date :
May 27, 2026, 12:17 p.m.
Last Modified :
May 27, 2026, 12:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-9689
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.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Restrict redirect URIs in Keycloak client configurations.
- Apply updates to Keycloak and client applications.
- Validate and sanitize all incoming user input.
- Implement strict URI validation.
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-2026-9689.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-9689 | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2481845 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-9689 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-2026-9689
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-2026-9689 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-9689 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]
May. 27, 2026
Action Type Old Value New Value Added Description A flaw was found in Keycloak, an open-source identity and access management solution. When a client application is configured to accept broad redirect Uniform Resource Identifiers (URIs), a remote attacker can manipulate the authentication process by crafting a special web address. If a user clicks this link, the client application might incorrectly prioritize attacker-controlled information over legitimate data. This vulnerability, known as HTTP parameter pollution, could allow an attacker to bypass security measures or gain unauthorized access to resources. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N Added CWE CWE-1288 Added Reference https://access.redhat.com/security/cve/CVE-2026-9689 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2481845