CVE-2026-47426: Openam oauth2 OpenAM OAuth Client Impersonation Vulnerability

HIGH
Advisory Identifier: GHSA-f2cx-463q-7m2c
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CWE-287
Published
Advisory Summary

CVE-2026-47426 is a HIGH openam oauth client impersonation vulnerability (CWE-287: Improper Authentication) affecting Openam oauth2 libraries in the Maven ecosystem. The issue involves openam oauth client impersonation via jwks resolver cache. Remediation is available by upgrading affected packages to version 16.1.1.

CVE-2026-47426 at a Glance

CVE Identifier CVE-2026-47426
GHSA Identifier GHSA-f2cx-463q-7m2c
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-287: Improper Authentication
Affected Product Openam oauth2
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-47426

To remediate this vulnerability, upgrade all affected Openam oauth2 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.openidentityplatform.openam:openam-oauth2 fixed: 16.1.1 
<dependency>
    <groupId>org.openidentityplatform.openam</groupId>
    <artifactId>openam-oauth2</artifactId>
    <version>16.1.1</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.openidentityplatform.openam

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-47426, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.openidentityplatform.openam

Analyze the terminal output to locate any version of Openam oauth2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 16.1.1), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.openidentityplatform.openam 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-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Openam oauth2, 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

## Summary **Description** An Improper Authentication (CWE-287) issue in OpenAM's OAuth2 private_key_jwt client authentication path allows any registered OAuth2 client to mint tokens in the name of any other client whose key is published via a jwks_uri, without knowing the victim's signing key. This affects OpenAM Community Edition through version 16.0.6 and was patched in version 16.1.1. ## Impact OpenAM Community Edition deployments through version 16.0.6 that have OAuth2 clients configured for private_key_jwt authentication with keys published via jwks_uri are potentially affected. An attacker holding any such client registration, their own, or one obtained through open dynamic client registration where enabled, can mint access tokens in any other such client's name, in any realm hosted by the OpenAM process. ## Patch This has been patched in OpenAM Community Edition version 16.1.1. Users are encouraged to update to the latest release.

CVE-2026-47426 Affected Openam oauth2 Versions

1 component(s)
Fixed Versions:
16.1.1
Product / Package Ecosystem Affected Versions Fixed Version
org.openidentityplatform.openam:openam-oauth2
maven/org.openidentityplatform.openam/openam-oauth2
Maven
< 16.1.1
16.1.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-f2cx-463q-7m2c
Openam oauth2 Source Repository REPOSITORY
https://github.com/OpenIdentityPlatform/OpenAM

Frequently Asked Questions

What is CVE-2026-47426?
CVE-2026-47426 is a security vulnerability in Openam oauth2 involving OpenAM OAuth Client Impersonation via JWKS Resolver Cache under CWE-287: Improper Authentication.
Which Openam oauth2 versions are affected?
Affected versions include releases prior to 16.1.1 across affected packages: org.openidentityplatform.openam:openam-oauth2.
What version fixes CVE-2026-47426?
Upgrading to 16.1.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openam-oauth2 affected?
Yes, org.openidentityplatform.openam:openam-oauth2 is affected in releases prior to 16.1.1. Upgrade your dependency to 16.1.1 or later.
What CWE is associated with CVE-2026-47426?
CVE-2026-47426 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check Maven dependencies for CVE-2026-47426?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.openidentityplatform.openam'. 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-f2cx-463q-7m2c",
  "modified" : "2026-06-29T17:44:37Z",
  "published" : "2026-06-29T17:44:37Z",
  "aliases" : [ "CVE-2026-47426" ],
  "summary" : "OpenAM OAuth Client Impersonation via JWKS Resolver Cache",
  "details" : "## Summary\n\n**Description**\n\nAn Improper Authentication (CWE-287) issue in OpenAM's OAuth2 private_key_jwt client authentication path allows any registered OAuth2 client to mint tokens in the name of any other client whose key is published via a jwks_uri, without knowing the victim's signing key. This affects OpenAM Community Edition through version 16.0.6 and was patched in version 16.1.1.\n\n## Impact\n\nOpenAM Community Edition deployments through version 16.0.6 that have OAuth2 clients configured for private_key_jwt authentication with keys published via jwks_uri are potentially affected. An attacker holding any such client registration, their own, or one obtained through open dynamic client registration where enabled, can mint access tokens in any other such client's name, in any realm hosted by the OpenAM process.\n\n## Patch\nThis has been patched in OpenAM Community Edition version 16.1.1. Users are encouraged to update to the latest release.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.openidentityplatform.openam:openam-oauth2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "16.1.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 16.0.6"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-f2cx-463q-7m2c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/OpenIdentityPlatform/OpenAM"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-29T17:44:37Z",
    "nvd_published_at" : null
  }
}