Keycloak on Red Hat improper validation of specified quantity in input

Summaryinfo

A vulnerability was found in Keycloak on Red Hat. It has been classified as problematic. The affected element is an unknown function. The manipulation leads to improper validation of specified quantity in input. This vulnerability is documented as CVE-2026-9801. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Keycloak on Red Hat (unknown version). This issue affects an unknown code block. The manipulation with an unknown input leads to a improper validation of specified quantity in input vulnerability. Using CWE to declare the problem leads to CWE-1284. The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties. Impacted is availability. The summary by CVE is:

A flaw was found in Keycloak. A remote attacker with high privileges, such as a realm administrator configuring a malicious Lightweight Directory Access Protocol (LDAP) server or an attacker compromising an upstream LDAP server, could exploit this vulnerability. By sending a malformed LDAP password policy response during a password authentication request, the attacker can trigger an OutOfMemoryError. This causes the Keycloak Java Virtual Machine (JVM) to terminate, leading to a denial of service (DoS) for all realms on the affected node.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-9801 since 05/28/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation needs additional levels of successful authentication. Neither technical details nor an exploit are publicly available.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-32718). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Keycloak

License

• open-source

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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