Red Hat build of Keycloak 26.4: Origin Validation Error
CVE-2026-16442 is a critical-severity origin validation error vulnerability in Red Hat build of Keycloak 26.4 from Red Hat, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Build Of Keycloak to 26.4.14 or 26.6.5, whichever matches your release line, or a later version.
- Read the advisory on access.redhat.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat build of Keycloak 26.4 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.4.14 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.6 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.6.5 | Not specified in the record | Not stated |
| Red Hat | Red Hat Data Grid 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7 | Not specified in the record | Not stated |
| Red Hat | Build Of Keycloak | 26.4 up to, but not including, 26.4.14; 26.6 up to, but not including, 26.6.5 | 26.4.14, 26.6.5 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.4 | High | CNA (redhat.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
A flaw was found in the SAML broker component of Keycloak, which is used to manage identity federation and user authentication. The issue occurs because the IdP-initiated Single Sign-On endpoint fails to check if a provider is restricted to account linking only. This allows an attacker with control over a linked upstream identity to bypass login restrictions and gain full access to a local user account.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Red Hat build of Keycloak 26.4
- 7.1 High severity
- 8.0 High severity
- 7.4 High severity
- 8.1 High severity
- 7.4 High severity
- 7.5 High severity
Recent Origin Validation Error vulnerabilities
- 8.8 High severity
- 9.4 Critical severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
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