CVE-2026-11800
Org.keycloak:keycloak-services: keycloak: authentication bypass via jwt algorithm confusion
Description
A flaw was found in Keycloak. This JWT algorithm confusion vulnerability in the JWT Authorization Grant flow allows an attacker with valid client credentials to bypass signature verification. By forging an assertion, the attacker can create unauthorized access tokens. This enables the attacker to impersonate any federated user linked to the affected Identity Provider, leading to unauthorized access and potential privilege escalation.
INFO
Published Date :
June 25, 2026, 8:57 p.m.
Last Modified :
June 25, 2026, 8:57 p.m.
Remotely Exploit :
Yes !
Source :
redhat
Affected Products
The following products are affected by CVE-2026-11800
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 | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Keycloak to a patched version.
- Verify JWT signature validation is correctly configured.
- Limit client credential exposure.
- Monitor for unauthorized access.
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-2026-11800 vulnerability anywhere in the article.