CVE-2024-27950: Sirv Auth Bypass Vulnerability

CVE-2024-27950 Overview

CVE-2024-27950 is a missing authorization vulnerability affecting the Sirv CDN and Image Hosting plugin for WordPress. The flaw impacts all versions of the sirv plugin from initial release through 7.2.0. Authenticated attackers with low privileges can invoke plugin functions that lack proper capability or authorization checks, resulting in broken access control [CWE-862]. Successful exploitation compromises confidentiality, integrity, and availability of the affected WordPress site. The vulnerability was published to the National Vulnerability Database (NVD) on March 1, 2024.

Critical Impact
An authenticated attacker with minimal privileges can bypass access controls in the Sirv plugin to perform actions restricted to higher-privileged users, potentially enabling site compromise.

Affected Products

Sirv CDN and Image Hosting plugin for WordPress
Versions from initial release through 7.2.0
WordPress sites with the sirv:sirv component installed

Discovery Timeline

2024-03-01 - CVE-2024-27950 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-27950

Vulnerability Analysis

The Sirv plugin exposes one or more action handlers that fail to validate the caller's authorization before executing privileged operations. This missing authorization check [CWE-862] permits any authenticated user, including low-privileged roles such as subscriber, to invoke functions intended for administrators. The Patchstack advisory classifies this as a broken access control flaw in the plugin's handler logic.

Because the vulnerable endpoints are reachable over the network via standard WordPress request paths, exploitation requires only valid session credentials and a crafted HTTP request. The attack complexity is low, and no user interaction is required to trigger the vulnerable code path.

Root Cause

The root cause is the absence of capability checks such as current_user_can() and nonce validation on privileged plugin actions. WordPress plugins commonly register handlers through admin_post_*, wp_ajax_*, or REST API routes. When these handlers omit authorization checks, WordPress executes them for any authenticated request that reaches them. In the affected versions of sirv, one or more such handlers proceed to sensitive operations without verifying the caller's role or capabilities.

Attack Vector

An attacker authenticates to the target WordPress site using any valid account, including a self-registered subscriber where open registration is enabled. The attacker then issues an HTTP POST request to the vulnerable plugin action endpoint. Because the handler does not verify authorization, the plugin executes the requested operation with the effective privilege of the plugin code rather than the caller. This yields the high confidentiality, integrity, and availability impact reflected in the CVSS metrics.

No verified public exploit code has been published for CVE-2024-27950. See the Patchstack Advisory for WordPress Sirv for the vendor-tracked technical details.

Detection Methods for CVE-2024-27950

Indicators of Compromise

Unexpected POST requests to wp-admin/admin-ajax.php or wp-admin/admin-post.php referencing Sirv plugin actions from low-privileged user sessions
New or modified media library entries, plugin options, or Sirv account settings without a corresponding administrator action
Outbound connections from the WordPress host to Sirv CDN endpoints initiated by non-administrative user contexts
Presence of the sirv plugin at version 7.2.0 or earlier in the WordPress plugin inventory

Detection Strategies

Inventory all WordPress installations and flag any running the sirv plugin at version <= 7.2.0
Correlate WordPress access logs with user role data to identify low-privileged accounts invoking Sirv admin actions
Alert on WordPress option changes, plugin setting modifications, and file uploads originating from non-administrator sessions
Monitor for anomalous account registrations followed shortly by requests to plugin AJAX handlers

Monitoring Recommendations

Forward WordPress and web server access logs to a centralized analytics platform for role-aware request analysis
Enable WordPress audit logging to record option changes, user role changes, and plugin configuration updates
Track HTTP 200 responses to Sirv plugin endpoints from unauthenticated or subscriber-level sessions
Baseline normal administrative activity and alert on deviations from that baseline

How to Mitigate CVE-2024-27950

Immediate Actions Required

Update the Sirv CDN and Image Hosting plugin to a version later than 7.2.0 on all WordPress installations
Audit existing user accounts, particularly subscriber and contributor roles, and disable any that are not required
Disable open user registration on public-facing WordPress sites unless explicitly required
Review WordPress and Sirv plugin settings for unauthorized modifications since March 2024

Patch Information

Refer to the Patchstack Vulnerability Report for Sirv for the fixed version and vendor remediation guidance. The advisory identifies versions up to and including 7.2.0 as vulnerable; upgrade to the vendor-supplied fixed release.

Workarounds

Deactivate and remove the Sirv plugin until the patched version can be deployed
Restrict access to wp-admin/admin-ajax.php and wp-admin/admin-post.php using web application firewall rules that enforce role-based access
Apply virtual patching rules from a WordPress-aware WAF to block requests targeting the vulnerable Sirv actions
Enforce multi-factor authentication on all WordPress accounts to raise the cost of credential-based access

bash

# Example: list WordPress sites running vulnerable Sirv versions using WP-CLI
wp plugin get sirv --field=version
# Upgrade the plugin once a fixed release is installed
wp plugin update sirv