CVE-2025-2559VulnerabilityPublished 29 Apr 2025Updated 31 Aug 2026

Red Hat Security Advisory: Red Hat build of Keycloak 26.0.11 Images Update

Affects Red HatSource GCVE Database

Mentioned vulnerabilities

Not known to be exploited : upgrade to 26.0.11 soon.

Data as of 25 Oct 2026, 19:02 UTC

Severity

High

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.7% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 26.0.11

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Apr 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Red Hat to 26.0.11.

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected >=26.0.0 <26.0.11	Fixed in 26.0.11

AI-suggested

Red Hat has released updated container images for Keycloak 26.0.11 that fix the identified vulnerabilities. Users should back up their existing installations, including applications, configuration files, and databases, before applying the update. Applying the updated images will mitigate the denial of service, hostname verification, and two-factor authentication bypass issues. No additional mitigation steps are indicated by the vendor advisory.

Description

Red Hat has released updated container images for the Red Hat build of Keycloak version 26.0.11, addressing multiple security issues. The fixes include a denial of service vulnerability caused by JWT token cache exhaustion, an issue with hostname verification, and a bypass in two-factor authentication. These updates are intended for use within the OpenShift Container Platform for on-premise or private cloud deployments. Users are advised to back up their existing installations before applying the updates.

Impact

Exploitation of these vulnerabilities could allow an attacker to cause a denial of service via JWT token cache exhaustion, bypass hostname verification potentially weakening authentication checks, and bypass two-factor authentication mechanisms. These issues could undermine the security of authentication services provided by Keycloak, affecting user account management and access control in web, mobile, and RESTful applications relying on Keycloak for authentication.

Summary

The Red Hat build of Keycloak 26.0.11 images have been updated to fix several security vulnerabilities. These include CVE-2025-2559, which involves JWT token cache exhaustion leading to a denial of service; CVE-2025-3501, a flaw in hostname verification; and CVE-2025-3910, a bypass in two-factor authentication. The advisory aligns the containerized images with the standalone product release and targets deployments on the OpenShift Container Platform. The update mitigates these vulnerabilities by releasing new images that address the identified issues.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
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.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-297Improper Validation of Certificate with Host Mismatch (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.
Architecture and Design
Fully check the hostname of the certificate and provide the user with adequate information about the nature of the problem and how to proceed.
Implementation
If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.14.1 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-287Improper Authentication (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Fake the Source of Data (opens in a new tab)
Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (opens in a new tab)
Session Hijacking (opens in a new tab)
Token Impersonation (opens in a new tab)
Upload a Web Shell to a Web Server (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Sep 2026, 22:32 UTC

WeaknessesCWE-770, CWE-297, CWE-287

Technical details

References

Community reviews

Related threats