CVE intelligence and bounded remediation

CVE-2023-6563 — An unconstrained memory consumption vulnerability was discovered in Keycloak

High CVSS 7.7

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.

Severity
High
CVSS
7.7 (3.1)
Published
2023-12-14
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-770

Affected products

  • redhat / keycloak
  • redhat / single_sign-on / 7.6
  • redhat / single_sign-on
  • redhat / openshift_container_platform / 4.11
  • redhat / openshift_container_platform / 4.12
  • redhat / openshift_container_platform_for_power / 4.9

Showing 6 representative product identities from 9 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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