CVE-2025-11850: Authentication Bypass Vulnerability

CVE-2025-11850 Overview

CVE-2025-11850 is an identity confusion vulnerability affecting WSO2 deployments that use secondary user stores. The implicit-association resolver incorrectly initializes from a secondary user store and bypasses the primary user store during search and uniqueness checks. When the same lookup claim, such as a username or email, exists in both the primary and a secondary store, a federated subject can be associated with an unintended local account. Deployments that do not configure secondary user stores, disable implicit association, or enforce globally unique claim values are not affected.

Critical Impact
Legitimate users authenticating through an external Identity Provider (IDP) may be implicitly linked to a lower-privileged secondary-store account, restricting access to their correct primary-store identity.

Affected Products

WSO2 products implementing the implicit-association resolver (see WSO2 Security Advisory WSO2-2025-4493)
Deployments configured with one or more secondary user stores
Deployments where the same claim value (username, email) exists across primary and secondary user stores

Discovery Timeline

2026-08-06 - CVE-2025-11850 published to NVD
2026-08-06 - Last updated in NVD database

Technical Details for CVE-2025-11850

Vulnerability Analysis

The defect lies in how the implicit-association resolver initializes its user-lookup context when secondary user stores are configured. Instead of searching the primary user store first and treating secondary stores as additional scopes, the resolver initializes directly from a secondary user store. Subsequent search operations and uniqueness checks then execute against that secondary store, skipping the primary store entirely.

The issue manifests during federated login when an external IDP returns a claim, such as username or email, that WSO2 must map to a local account. If the same claim value exists in both a primary and a secondary store, the resolver associates the federated subject with the secondary-store account. This is a business logic and access-control flaw rather than a memory-safety issue.

Root Cause

The root cause is incorrect initialization order in the implicit-association resolver. The resolver treats a secondary user store as the authoritative source for lookup and uniqueness validation. Because the primary user store is never consulted, duplicate claim values across stores resolve to the wrong identity.

Attack Vector

Exploitation requires a deployment that satisfies three preconditions: implicit association is enabled, secondary user stores are configured, and duplicate claim values exist across stores. An external user authenticating through a federated IDP with a claim value that collides with a secondary-store account will be silently associated with that secondary account. The condition can arise from misconfiguration, migration overlap, or deliberate creation of a colliding account in a secondary store. Successful exploitation results in identity confusion and, depending on the privileges of the secondary account, either restricted or unintended access. See the WSO2 Security Advisory for vendor-specific technical details.

Detection Methods for CVE-2025-11850

Indicators of Compromise

Federated login events where the resolved local user belongs to a secondary user store despite a matching account existing in the primary store.
Authentication audit entries showing repeated implicit-association actions targeting the same claim value across different stores.
User complaints of missing entitlements or unexpected role sets immediately after IDP-based sign-in.

Detection Strategies

Correlate IDP assertion claims with the userstore attribute of the resolved local subject in WSO2 audit logs.
Query the identity store for duplicate values of association claims such as username and email across primary and secondary stores.
Alert on federated authentication sessions whose resolved account privileges deviate from the expected role for that IDP subject.

Monitoring Recommendations

Enable and retain WSO2 authentication and provisioning audit logs, including implicit-association events, in a centralized log platform.
Monitor configuration changes to secondary user store definitions and to the implicit-association feature flag.
Track first-time associations between federated subjects and local accounts, treating cross-store bindings as high-signal events for review.

How to Mitigate CVE-2025-11850

Immediate Actions Required

Review the WSO2 Security Advisory WSO2-2025-4493 and apply the fix listed for your product and version.
Inventory all configured user stores and identify overlapping claim values between the primary and any secondary store.
Audit existing federated-to-local account associations and remediate any that resolved to an unintended secondary-store account.

Patch Information

Refer to the WSO2 Security Advisory WSO2-2025-4493 for the authoritative list of fixed product versions and upgrade guidance. Apply the vendor patch on all affected nodes and restart the identity server as directed by WSO2.

Workarounds

Disable the implicit-association feature if federated identity mapping can be handled through explicit account linking.
Remove secondary user store configurations if they are not required for the deployment.
Enforce globally unique values for association claims such as username and email across every configured user store.
Restrict secondary user store accounts to the minimum privileges necessary until the patch is applied.

bash

# Configuration example
# Refer to the WSO2 Security Advisory WSO2-2025-4493 for vendor-supplied
# configuration steps to disable implicit association or to restrict
# secondary user store scope during resolver initialization.