CVE-2026-11800: Org.keycloak:keycloak-services: keycloak: authentication bypass via jwt algorithm confusion
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-11 15:49 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by redhat, published 2026-06-25).
Weakness: Improper Verification of Cryptographic Signature
How it can be exploited
Exploitable over the network with low attack complexity needing low privileges and no user interaction. Impact: confidentiality high, integrity high, availability none. CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: total.
Public exploit evidence (Exploit Observer)
Exploit Observer found 2 code repositories naming this CVE.
Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.
See all 9 references on Exploit Observer
Live scores
- EPSS
- 0.003
low predicted chance of attack - VEDAS
- 0.975
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Red Hat build of Keycloak 26.6 (rhbk/keycloak-operator-bundle) | Not stated | 26.6.4-2 is not affected (up to *) |
| Red Hat build of Keycloak 26.6 (rhbk/keycloak-rhel9) | Not stated | 26.6-8 is not affected (up to *) |
| Red Hat build of Keycloak 26.6 (rhbk/keycloak-rhel9-operator) | Not stated | 26.6-8 is not affected (up to *) |
| Red Hat build of Keycloak 26.6.4 | Not stated | Not stated |
| Red Hat Build of Keycloak (rhbk/keycloak-rhel9) | Not stated | Not stated |
| Red Hat Build of Keycloak (rhbk-openshift-rhel9/rhbk-openshift-rhel9) | Not stated | Not stated |
| Red Hat Data Grid 8 (keycloak-services) | Not stated | Not stated |
| Red Hat JBoss Enterprise Application Platform Expansion Pack (keycloak-services) | Not stated | Not stated |
| Red Hat Single Sign-On 7 (keycloak-services) | Not stated | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
Vendor guidance:
- RHSA-2026:30083 (vendor-advisory, x_refsource_REDHAT)
- RHSA-2026:30084 (vendor-advisory, x_refsource_REDHAT)
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
References
Vendor advisories and patches
- RHSA-2026:30083 (vendor-advisory, x_refsource_REDHAT)
- RHSA-2026:30084 (vendor-advisory, x_refsource_REDHAT)
Technical analysis and advisories
- RHBZ#2487006 (issue-tracking, x_refsource_REDHAT)
Other references
- https://access.redhat.com/security/cve/CVE-2026-11800 (vdb-entry, x_refsource_REDHAT)
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-11800.json (x_sadp-csaf-vex)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
Supporting partners
