CVE-2023-6563

HighCVSS 7.7/10Last modified Sep 22, 2026

Description

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.

Metrics

CVSS 3.1 7.7/10CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Weakness enumeration

CWE-770

Affected software

VendorProductVersions
Red HatRed Hat Single Sign-On 7.6 for RHEL 7—
Red HatRed Hat Single Sign-On 7.6 for RHEL 8—
Red HatRed Hat Single Sign-On 7.6 for RHEL 9—
Red HatRHEL-8 based Middleware Containers—
Red HatRHEL-8 based Middleware Containers—
Red HatSingle Sign-On 7.6.6—
Red HatRed Hat Build of Keycloak—

References

Timeline

Published
Dec 14, 2023
Last modified
Sep 22, 2026
NVD status
Modified

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CVE-2023-6563: High severity, CVSS 7.7 | Vulnix