CVE-2026-3872
Keycloak: keycloak: information disclosure due to redirect_uri validation bypass
Description
A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure.
INFO
Published Date :
April 2, 2026, 1:16 p.m.
Last Modified :
April 16, 2026, 8:52 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-3872
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 | HIGH | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Keycloak to a patched version.
- Review and restrict redirect URI patterns.
- Implement stricter validation on redirect URIs.
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-2026-3872.
| URL | Resource |
|---|---|
| https://access.redhat.com/errata/RHSA-2026:6475 | Vendor Advisory |
| https://access.redhat.com/errata/RHSA-2026:6476 | Vendor Advisory |
| https://access.redhat.com/errata/RHSA-2026:6477 | Vendor Advisory |
| https://access.redhat.com/errata/RHSA-2026:6478 | Vendor Advisory |
| https://access.redhat.com/security/cve/CVE-2026-3872 | Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2445988 | Issue Tracking Vendor 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-2026-3872 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-2026-3872
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-2026-3872 vulnerability anywhere in the article.
-
Daily CyberSecurity
Keycloak Under Siege: Patch Now to Stop Token Theft and Account Takeovers
The popular open-source identity and access management solution Keycloak has released a critical security update, version 26.5.7, addressing a series of vulnerabilities that could allow attackers to b ... Read more
The following table lists the changes that have been made to the
CVE-2026-3872 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.
-
Initial Analysis by [email protected]
Apr. 16, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:* *cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:* Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:6475 Types: Vendor Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:6476 Types: Vendor Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:6477 Types: Vendor Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/errata/RHSA-2026:6478 Types: Vendor Advisory Added Reference Type Red Hat, Inc.: https://access.redhat.com/security/cve/CVE-2026-3872 Types: Vendor Advisory Added Reference Type Red Hat, Inc.: https://bugzilla.redhat.com/show_bug.cgi?id=2445988 Types: Issue Tracking, Vendor Advisory -
CVE Modified by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:6475 Added Reference https://access.redhat.com/errata/RHSA-2026:6476 -
CVE Modified by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:6477 Added Reference https://access.redhat.com/errata/RHSA-2026:6478 -
New CVE Received by [email protected]
Apr. 02, 2026
Action Type Old Value New Value Added Description A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Added CWE CWE-601 Added Reference https://access.redhat.com/security/cve/CVE-2026-3872 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2445988