Red Hat build of Keycloak 26.4: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
CVE-2026-16102 is a high-severity incorrect behavior order: authorization before parsing and canonicalization vulnerability in Red Hat build of Keycloak 26.4 from Red Hat, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.46% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
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.
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 |
| Red Hat | Data Grid | 8.0 | Not stated |
| Red Hat | Jboss Enterprise Application Platform Expansion Pack | Not specified in the record | Not stated |
| Red Hat | Single Sign-on | 7.0 | Not stated |
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
- LowA basic user account is enough.
- 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (redhat.com).
Official description
A flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management solution. The default DCR policy fails to properly validate the claim path for User Property mappers, allowing them to write values to sensitive internal claim locations. An attacker with a standard user account and a limited Initial Access Token can exploit this to forge administrative roles in their access token. This allows the attacker to take over other clients, steal confidential secrets, and potentially gain full administrative control over the realm.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
If a web server does not fully parse requested URLs before it examines them for authorization, it may be possible for an attacker to bypass authorization protection.
How developers prevent this class of flaw
- URL Inputs should be decoded and canonicalized to the application's current internal representation before being validated and processed for authorization. Make sure that your application does not decode the same input twice. Such errors could be used to bypass allowlist schemes by introducing dangerous inputs after they have been checked.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
- bugzilla.redhat.com/show_bug.cgi?id=2501735Issue Tracking
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 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization vulnerabilities
- 8.1 High severity
- 8.1 High severity
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