CVE-2026-18963: Keycloak Unauthenticated Account Takeover Vulnerability
CRITICALCVE-2026-18963 is a CRITICAL (CVSS 9.1) unauthenticated account takeover vulnerability (CWE-640: Weak Password Recovery Mechanism for Forgotten Password) affecting Keycloak libraries in the Maven ecosystem. The issue involves unauthenticated account takeover via reset-credentials flow bypass. Remediation is available by upgrading affected packages to version 26.4.15, 26.6.6, 26.7.2.
CVE-2026-18963 at a Glance
Security Impact
CVSS: 9.1
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).
How to Fix CVE-2026-18963
To remediate this vulnerability, upgrade all affected Keycloak dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
<dependency>
<groupId>org.keycloak</groupId>
<artifactId>keycloak-services</artifactId>
<version>26.4.15</version>
</dependency><dependency>
<groupId>org.keycloak</groupId>
<artifactId>keycloak-services</artifactId>
<version>26.6.6</version>
</dependency><dependency>
<groupId>org.keycloak</groupId>
<artifactId>keycloak-services</artifactId>
<version>26.7.2</version>
</dependency>Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=org.keycloakHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-18963, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=org.keycloakAnalyze the terminal output to locate any version of Keycloak in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 26.4.15), your application is affected.
Note: The mvn dependency:tree -Dincludes=org.keycloak command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-640: Weak Password Recovery Mechanism for Forgotten Password, where the product contains a mechanism for users to recover or change their passwords without knowing the original password, but the mechanism is weak. In Keycloak, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-18963 Affected Keycloak Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
org.keycloak:keycloak-services
|
Maven |
≥ 26.0.0
< 26.4.15
|
26.4.15
|
|
org.keycloak:keycloak-services
|
Maven |
≥ 26.5.0
< 26.6.6
|
26.6.6
|
|
org.keycloak:keycloak-services
|
Maven |
≥ 26.7.0
< 26.7.2
|
26.7.2
|
References
Frequently Asked Questions
What is CVE-2026-18963?
Which Keycloak versions are affected?
What version fixes CVE-2026-18963?
Is keycloak-services affected?
What is the CVSS score of CVE-2026-18963?
What CWE is associated with CVE-2026-18963?
How can I check Maven dependencies for CVE-2026-18963?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-4gv3-mc9p-5wqc",
"modified" : "2026-08-28T22:53:41Z",
"published" : "2026-08-18T18:32:00Z",
"aliases" : [ "CVE-2026-18963" ],
"summary" : "Keycloak: Unauthenticated account takeover via reset-credentials flow bypass",
"details" : "A flaw was found in the reset-credentials flow of the keycloak-services component, which is the core engine for identity and access management in Red Hat Build of Keycloak. The issue allows an unauthenticated attacker to force the password reset process for any user without needing to click the required email verification link. This can result in the attacker gaining full control over target user accounts by directly setting new credentials.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "org.keycloak:keycloak-services"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "26.0.0"
}, {
"fixed" : "26.4.15"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.keycloak:keycloak-services"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "26.5.0"
}, {
"fixed" : "26.6.6"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Maven",
"name" : "org.keycloak:keycloak-services"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "26.7.0"
}, {
"fixed" : "26.7.2"
} ]
} ]
} ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18963"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/issues/51833"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/pull/51844"
}, {
"type" : "WEB",
"url" : "https://github.com/keycloak/keycloak/commit/dc2d4e524b4dae85aedc87ca28b9e4fa567d56c1"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:56519"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:56520"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:56523"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/errata/RHSA-2026:56524"
}, {
"type" : "WEB",
"url" : "https://access.redhat.com/security/cve/CVE-2026-18963"
}, {
"type" : "WEB",
"url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2511595"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/keycloak/keycloak"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-640" ],
"severity" : "CRITICAL",
"github_reviewed" : true,
"github_reviewed_at" : "2026-08-28T22:53:41Z",
"nvd_published_at" : "2026-08-18T17:16:57Z"
}
}