CVE-2026-37982: Keycloak Unauthorized Account Takeover Vulnerability

MODERATE
Advisory Identifier: GHSA-w4p5-rfh6-cwrv
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CVSS 6.8
CWE-294
Published
Advisory Summary

CVE-2026-37982 is a MODERATE (CVSS 6.8) unauthorized account takeover vulnerability (CWE-294: Authentication Bypass by Capture-replay) affecting Keycloak libraries in the Maven ecosystem. The issue involves unauthorized account takeover via webauthn token replay. Remediation is available by upgrading affected packages to version 26.6.2.

CVE-2026-37982 at a Glance

CVE Identifier CVE-2026-37982
GHSA Identifier GHSA-w4p5-rfh6-cwrv
Severity MODERATE
CVSS v3.1 Base Score 6.8
CWE Classification CWE-294: Authentication Bypass by Capture-replay
Affected Product Keycloak
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 6.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-37982

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.

org.keycloak:keycloak-services fixed: 26.6.2 
<dependency>
    <groupId>org.keycloak</groupId>
    <artifactId>keycloak-services</artifactId>
    <version>26.6.2</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree -Dincludes=org.keycloak

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-37982, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.keycloak

Analyze 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 26.6.2), 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-294: Authentication Bypass by Capture-replay, where a capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes). 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

A flaw was found in Keycloak. This authentication vulnerability allows a remote attacker to replay `ExecuteActionsActionToken` tokens within Keycloak's WebAuthn (Web Authentication) flow. By intercepting an execute-actions email link, an attacker can register their own authenticator to a victim's account. This leads to unauthorized enrollment of a hardware-backed credential, enabling persistent account takeover.

CVE-2026-37982 Affected Keycloak Versions

1 component(s)
Fixed Versions:
26.6.2
Product / Package Ecosystem Affected Versions Fixed Version
org.keycloak:keycloak-services
maven/org.keycloak/keycloak-services
Maven
< 26.6.2
26.6.2

References

NVD — CVE-2026-37982 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-37982
Keycloak Source Repository REPOSITORY
https://github.com/keycloak/keycloak/pull/49126
Security Fix Commit FIX COMMIT
https://github.com/keycloak/keycloak/commit/2d1a24f501454a44c52daa62855419b31dc499c1
access.redhat.com/errata/rhsa-2026:19... WEB
https://access.redhat.com/errata/RHSA-2026:19596
access.redhat.com/errata/rhsa-2026:19... WEB
https://access.redhat.com/errata/RHSA-2026:19597
Keycloak Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-37982
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2455329
Keycloak Source Repository REPOSITORY
https://github.com/keycloak/keycloak
Keycloak Release RELEASE
https://github.com/keycloak/keycloak/releases/tag/26.6.2

Frequently Asked Questions

What is CVE-2026-37982?
CVE-2026-37982 is a security vulnerability in Keycloak involving Unauthorized account takeover via WebAuthn token replay under CWE-294: Authentication Bypass by Capture-replay.
Which Keycloak versions are affected?
Affected versions include releases prior to 26.6.2 across affected packages: org.keycloak:keycloak-services.
What version fixes CVE-2026-37982?
Upgrading to 26.6.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is keycloak-services affected?
Yes, org.keycloak:keycloak-services is affected in releases prior to 26.6.2. Upgrade your dependency to 26.6.2 or later.
What is the CVSS score of CVE-2026-37982?
CVE-2026-37982 has a CVSS v3.1 base score of 6.8 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-37982?
CVE-2026-37982 is classified under CWE-294: Authentication Bypass by Capture-replay (A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).).
How can I check Maven dependencies for CVE-2026-37982?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.keycloak'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w4p5-rfh6-cwrv",
  "modified" : "2026-06-04T15:35:19Z",
  "published" : "2026-05-19T12:31:40Z",
  "aliases" : [ "CVE-2026-37982" ],
  "summary" : "Keycloak: Unauthorized account takeover via WebAuthn token replay",
  "details" : "A flaw was found in Keycloak. This authentication vulnerability allows a remote attacker to replay `ExecuteActionsActionToken` tokens within Keycloak's WebAuthn (Web Authentication) flow. By intercepting an execute-actions email link, an attacker can register their own authenticator to a victim's account. This leads to unauthorized enrollment of a hardware-backed credential, enabling persistent account takeover.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.keycloak:keycloak-services"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "26.6.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-37982"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/pull/49126"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/commit/2d1a24f501454a44c52daa62855419b31dc499c1"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:19596"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:19597"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-37982"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2455329"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/keycloak/keycloak"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/keycloak/keycloak/releases/tag/26.6.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-294" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-04T15:35:19Z",
    "nvd_published_at" : "2026-05-19T12:16:18Z"
  }
}