Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.69% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-2559High confidence
Org.keycloak/keycloak-services: jwt token cache exhaustion leading to denial of service (dos) in keycloak
Red Hat · Red Hat Build of Keycloak
Official source article: Red Hat RHSA-2025:4335 ↗. Check the applicable product and release in the original source.
4.9MediumCVSS 3.1
Scheduled
Patch availableMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Red Hat Red Hat Build of Keycloak and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Open-source package ranges1 source-attributed range
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| mavenorg.keycloak:keycloak-services | <= 26.1.4 | Not stated | GitHub advisory ↗github reviewed aggregator · 30 Apr 2025 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2025-2559 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityorg.keycloak/keycloak-services: JWT Token Cache Exhaustion Leading to Denial of Service (DoS) in Keycloak
The vendor explicitly identifies these products as affected by this CVE.
- keycloak-services as a component of Red Hat Single Sign-On 7
- Summary
- 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.
- Remediation
- Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch available01
What, why and how
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
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.
Why
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
How
An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.
What
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.
Why
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
How
An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Allocation of Resources Without Limits or Throttling → disrupt the affected service
- Attack surface
- Network
- Privileges required
- High: elevated access is required
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-770 ↗
CWE-770: Allocation of Resources Without Limits or Throttling. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Fixed
- rhbk/keycloak-operator-bundle@sha256:67a4498b9c68a7068cc2bcfa2d7d5eb35e6ec7e281c0886893f4125a6487c8a1_amd64 as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9-operator@sha256:83c90cf0627a1b99900d539f417e648d8be4c9966452872a93a8236e17b1d1cf_amd64 as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9-operator@sha256:8e1a37dc9fa7b99a65ac9997d49bc9991172a461c63196614d1975bc2210e7fa_ppc64le as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9-operator@sha256:acd2a3adf7365e62689b79608c2289c804f47f97a81f9e8ddf3fecdce6d6f0ec_s390x as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9@sha256:67699f3ec6e1a489b769523d9deaeec57a8113259d375501aa043778828c2286_amd64 as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9@sha256:76f2963c284d0a79e6026bee0837639bce5af84a18c994828aa0890923725189_s390x as a component of Red Hat build of Keycloak 26.0
- rhbk/keycloak-rhel9@sha256:87ff67880fd7f44174b263759c99f4d701cf208eeb6f4abf636a10b98ec023d0_ppc64le as a component of Red Hat build of Keycloak 26.0
- Red Hat Build of Keycloak
- Action
- Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 25 Mar 2025 · Last source change 21 Sept 2026, 05:47 UTC · CWE-770 · Allocation of Resources Without Limits or Throttling
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2025-8064
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD not scheduled
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.CNA ↗
- Before
- 23.0.0 < 26.0.11; 26.1.0 < 26.1.5 · Fixed: 26.0.11-2 < *; 26.0-12 < *; 26.0-13 < *
- After
- 23.0.0 < 26.0.11, 26.1.0 < 26.1.5 · Fixed: Red Hat build of Keycloak 26.0: 26.0.11-2 < *, 26.0-12 < *, 26.0-13 < *
CVE published
Fixed release or patch reference recorded
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.