CVE-2025-31618: CiviCRM CiviMcRestFace Auth Bypass Flaw

CVE-2025-31618 Overview

CVE-2025-31618 is a missing authorization vulnerability in the Jaap Jansma Connector to CiviCRM with CiviMcRestFace WordPress plugin. The flaw affects all versions up to and including 1.0.10. The plugin fails to enforce correct access control checks, allowing unauthenticated attackers to reach functionality that should be restricted. Successful exploitation can result in limited unauthorized modification of plugin data over the network. The weakness is categorized under CWE-862: Missing Authorization.

Critical Impact
Unauthenticated network attackers can exploit incorrectly configured access control to affect integrity of the CiviCRM connector, without user interaction or elevated privileges.

Affected Products

Jaap Jansma Connector to CiviCRM with CiviMcRestFace plugin for WordPress
All versions from initial release through 1.0.10
WordPress sites integrating CiviCRM through the CiviMcRestFace connector

Discovery Timeline

2025-03-31 - CVE-2025-31618 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-31618

Vulnerability Analysis

The vulnerability stems from the plugin exposing functionality without validating the caller's authorization. The Connector to CiviCRM with CiviMcRestFace plugin bridges WordPress with CiviCRM through the CiviMcRestFace API layer. One or more plugin endpoints lack a capability or nonce check before executing sensitive operations. This omission allows any unauthenticated requester to reach protected code paths. The impact is limited to integrity, meaning attackers can alter plugin state or data but cannot directly extract confidential information or crash the service through this flaw.

Root Cause

The root cause is the absence of an authorization gate on plugin request handlers, an issue tracked as CWE-862: Missing Authorization. Endpoints that should validate user capabilities via current_user_can(), verify a WordPress nonce with wp_verify_nonce(), or otherwise enforce access levels do not perform these checks. As a result, security decisions rely on obscurity of the endpoint rather than enforced policy.

Attack Vector

Exploitation occurs remotely over the network. An attacker sends crafted HTTP requests to the vulnerable plugin endpoint on any WordPress site running an affected version. No credentials, user interaction, or social engineering are required. The attacker does not need prior access to the WordPress dashboard. Because the connector interacts with CiviCRM data flows, unauthorized invocation of these routes can influence configuration or connector behavior linked to the CRM integration. Refer to the Patchstack Vulnerability Report for endpoint-specific details.

Detection Methods for CVE-2025-31618

Indicators of Compromise

Unauthenticated HTTP requests to Connector to CiviCRM with CiviMcRestFace plugin routes under /wp-content/plugins/connector-civicrm-mcrestface/ or associated REST paths
Unexpected changes to plugin configuration or CiviCRM connector settings without a corresponding administrator session
Access log entries showing repeated POST or GET traffic to plugin endpoints from unfamiliar IP addresses

Detection Strategies

Audit WordPress plugin inventory to identify hosts running connector-civicrm-mcrestface at version 1.0.10 or earlier
Inspect web server and WordPress access logs for requests to plugin endpoints lacking an authenticated cookie or valid nonce
Correlate CiviCRM audit events with WordPress user sessions to identify actions with no matching authenticated origin

Monitoring Recommendations

Enable verbose logging on the WordPress REST API and admin-ajax handlers to capture caller identity and referrer data
Alert on HTTP 200 responses to plugin routes when the request lacks an authenticated session
Monitor for spikes in traffic to the plugin's URI patterns from external sources

How to Mitigate CVE-2025-31618

Immediate Actions Required

Update the Connector to CiviCRM with CiviMcRestFace plugin to a fixed version released after 1.0.10 as soon as it is available
If no patched version is published, deactivate and remove the plugin from all affected WordPress installations
Review CiviCRM connector configuration and audit recent changes for signs of unauthorized modification

Patch Information

At the time of publication, the vulnerability affects all versions through 1.0.10. Administrators should consult the Patchstack Vulnerability Report for the latest fixed release information and vendor guidance.

Workarounds

Restrict access to the WordPress site's plugin endpoints using a web application firewall rule that blocks unauthenticated requests to connector-civicrm-mcrestface paths
Apply IP allowlisting on the WordPress admin and REST API surfaces to limit exposure while a fix is pending
Rotate any CiviCRM API keys or credentials referenced by the connector if unauthorized activity is suspected

bash

# Example WAF rule (ModSecurity) to block unauthenticated access to the plugin
SecRule REQUEST_URI "@contains /wp-content/plugins/connector-civicrm-mcrestface/" \
    "id:1003162,phase:1,deny,status:403,\
     chain,msg:'Block unauthenticated access to vulnerable CiviCRM connector (CVE-2025-31618)'"
    SecRule &REQUEST_COOKIES:/wordpress_logged_in_/ "@eq 0"