Red Hat build of Keycloak 26.2: Improper Validation of Syntactic Correctness of Input
CVE-2026-7307 is a high-severity improper validation of syntactic correctness of input vulnerability in Red Hat build of Keycloak 26.2 from Red Hat, with a CVSS 3.1 base score of 7.5 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 0.88% chance of exploitation within 30 days, higher than 60% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Build Of Keycloak to 26.4.12 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 26.2 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.2.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.4 | Not specified in the record | Not stated |
| Red Hat | Red Hat build of Keycloak 26.4.12 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6.13 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Single Sign-On 7.6 for RHEL 9 | Not specified in the record | Not stated |
| Red Hat | RHEL-8 based Middleware Containers | Not specified in the record | Not stated |
| Red Hat | Build Of Keycloak | 26.4 up to, but not including, 26.4.12 | 26.4.12 |
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
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (redhat.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.5 | High | CNA |
Official description
A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Validation of Syntactic Correctness of Input
The product receives input that is expected to be well-formed - i.e., to comply with a certain syntax - but it does not validate or incorrectly validates that the input complies with the syntax.
More Improper Validation of Syntactic Correctness of Input vulnerabilities (CWE-1286)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in Red Hat build of Keycloak 26.2
- 7.5 High severity
- 8.1 High severity
- 8.1 High severity
- 7.5 High severity
- 7.4 High severity
- 7.3 High severity
Recent Improper Validation of Syntactic Correctness of Input vulnerabilities
- 7.1 High severity
- 8.3 High severity
- 7.5 High severity
- 7.5 High severity
- 7.2 High severity
- 7.5 High severity
Spotted an error? Tell us.