CVE-2025-26926: Booknetic CSRF Vulnerability

CVE-2025-26926 Overview

CVE-2025-26926 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Booknetic WordPress plugin developed by fs-code. The flaw exists in all versions up to and including 4.0.9. The weakness is classified under [CWE-352], indicating missing or improperly implemented CSRF protections on state-changing requests.

An attacker can craft a malicious page or link that triggers unwanted actions in the plugin when an authenticated user visits it. Exploitation requires user interaction, and the impact is limited to integrity, with no direct confidentiality or availability effects.

Critical Impact

Authenticated users tricked into visiting an attacker-controlled page may unknowingly perform state-changing actions within the Booknetic plugin, altering booking data or plugin state.

Affected Products

• fs-code Booknetic plugin for WordPress
• Booknetic versions from initial release through 4.0.9
• WordPress sites with the vulnerable Booknetic plugin installed and active

Discovery Timeline

• 2025-02-25 - CVE-2025-26926 published to the National Vulnerability Database (NVD)
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-26926

Vulnerability Analysis

The vulnerability is a Cross-Site Request Forgery flaw in the Booknetic WordPress plugin. Booknetic is a commercial appointment booking plugin used by WordPress site administrators to manage services, staff, and reservations. The affected endpoints do not validate anti-CSRF tokens on state-changing operations, allowing an attacker to forge requests that execute in the context of an authenticated user's browser session.

The issue is exploitable over the network and requires user interaction. According to the EPSS data (0.149%, percentile 4.57), the probability of exploitation activity in the near term is currently low. Successful exploitation results in a limited integrity impact and does not directly expose data or cause denial of service.

Root Cause

The root cause is the absence or improper verification of a CSRF token (such as a WordPress nonce) on requests that modify plugin state. Without validating the origin or authenticity of the request, the plugin accepts any well-formed HTTP request accompanied by valid session cookies as legitimate. This design flaw is characteristic of [CWE-352].

Attack Vector

An attacker hosts a page containing hidden form submissions, image tags, or JavaScript that issue requests to the vulnerable Booknetic endpoints. When an authenticated Booknetic user (typically a site administrator or staff member) visits the attacker-controlled page, the browser automatically attaches session cookies to the forged request. The plugin then processes the request as if the user initiated it, allowing the attacker to modify plugin state without direct access.

No verified proof-of-concept code is publicly available. See the Patchstack advisory for Booknetic CSRF for additional technical context.

Detection Methods for CVE-2025-26926

Indicators of Compromise

• Unexpected changes to Booknetic bookings, services, staff configuration, or plugin settings without corresponding admin activity in logs
• HTTP POST or GET requests to Booknetic admin-ajax endpoints originating with Referer headers pointing to external, untrusted domains
• Session cookies present on requests to Booknetic endpoints from browsers that also loaded suspicious third-party pages shortly before the request

Detection Strategies

• Review web server access logs for requests to Booknetic administrative endpoints where the Referer header is missing or points to an unrelated origin
• Correlate WordPress audit logs with browsing telemetry to identify state changes triggered shortly after visits to untrusted URLs
• Deploy a Web Application Firewall (WAF) rule set that flags requests to plugin endpoints lacking valid WordPress nonces

Monitoring Recommendations

• Enable a WordPress activity logging plugin to track configuration and content changes performed by administrator and staff accounts
• Monitor outbound proxy or DNS logs for administrator workstations visiting unknown or newly registered domains during work sessions
• Alert on any modification to Booknetic plugin database tables outside of normal maintenance windows

How to Mitigate CVE-2025-26926

Immediate Actions Required

• Update the Booknetic plugin to a version later than 4.0.9 as soon as the vendor publishes a patched release
• Restrict Booknetic administrative access to trusted IP ranges where feasible using WordPress or web server access controls
• Instruct administrators and staff to log out of the WordPress admin dashboard when not actively using it to reduce the window for CSRF exploitation

Patch Information

Refer to the Patchstack advisory for Booknetic CSRF for the latest patch availability and fixed version details. Site owners should apply the vendor-supplied update as soon as it is released and verify the installed version is greater than 4.0.9.

Workarounds

• Deploy a WAF or plugin-level rule that requires a valid Referer or Origin header matching the WordPress site domain on Booknetic state-changing requests
• Enforce short session lifetimes for WordPress administrators and require reauthentication for sensitive Booknetic operations
• Temporarily deactivate the Booknetic plugin on sites where administrator activity cannot be tightly controlled until a fixed version is installed

# Example WAF rule concept (ModSecurity) to enforce same-origin requests to Booknetic endpoints
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
  "chain,deny,status:403,id:1002601,msg:'Booknetic CSRF - missing or invalid Origin'"
SecRule ARGS:action "@rx ^booknetic" "chain"
SecRule &REQUEST_HEADERS:Origin "@eq 0"