CVE-2026-57747: Booked Scheduler CSRF Vulnerability

CVE-2026-57747 Overview

CVE-2026-57747 is an unauthenticated Cross-Site Request Forgery (CSRF) vulnerability affecting the Booked WordPress plugin versions 3.0.0 and earlier. The flaw is classified under CWE-352 and allows attackers to trigger unwanted state-changing actions in the plugin when an authenticated user is tricked into visiting a crafted page. Successful exploitation requires user interaction but no privileges or authentication on the attacker's side. The vulnerability impacts availability of the affected WordPress site but does not directly expose confidential data or allow data modification without secondary conditions.

Critical Impact
An unauthenticated attacker can coerce an authenticated victim's browser to submit forged requests to the Booked plugin, leading to high-impact availability disruption.

Affected Products

Booked WordPress plugin versions <= 3.0.0
WordPress installations with the Booked appointment booking plugin enabled
Sites relying on Booked for reservation and scheduling workflows

Discovery Timeline

2026-07-02 - CVE CVE-2026-57747 published to NVD
2026-07-02 - Last updated in NVD database

Technical Details for CVE-2026-57747

Vulnerability Analysis

The vulnerability stems from missing or improper Cross-Site Request Forgery protection in the Booked WordPress plugin through version 3.0.0. State-changing endpoints in the plugin accept requests without validating a properly scoped anti-CSRF token or nonce tied to the authenticated user's session. An attacker can craft a malicious page or link that, when visited by an authenticated WordPress user with access to the Booked plugin, causes the victim's browser to submit forged requests. Because the requests carry the victim's session cookies, the plugin processes them as legitimate.

The impact profile focuses on availability. Confidentiality and integrity are not directly affected, but availability can be significantly degraded through forced actions such as bulk booking manipulation or configuration changes that disrupt service.

Root Cause

The root cause is the absence of WordPress nonce verification (or equivalent CSRF protection) on sensitive Booked plugin endpoints. WordPress provides wp_nonce_field() and check_admin_referer() primitives, but affected code paths in Booked <= 3.0.0 do not enforce these checks before performing privileged operations. This aligns with the standard CWE-352 pattern.

Attack Vector

Exploitation occurs over the network and requires user interaction. An attacker hosts a malicious page containing an auto-submitting form or crafted request targeting a Booked plugin endpoint. When an authenticated WordPress user visits the page, their browser sends the forged request with valid session cookies. See the Patchstack CVE Analysis for additional technical context.

Detection Methods for CVE-2026-57747

Indicators of Compromise

Unexpected changes to Booked plugin configuration, appointments, or bookings without corresponding administrator activity logs
HTTP POST or GET requests to Booked plugin endpoints originating from unusual Referer headers pointing to external domains
Spikes in state-changing requests to /wp-admin/admin-ajax.php or Booked-specific endpoints from a single authenticated session

Detection Strategies

Inspect web server access logs for requests to Booked plugin endpoints where the Referer header does not match the site's own domain
Correlate WordPress audit logs with unexpected booking modifications or plugin setting changes
Deploy a Web Application Firewall (WAF) rule to flag state-changing requests lacking a valid WordPress nonce parameter

Monitoring Recommendations

Enable WordPress activity logging plugins to capture administrative and plugin-level changes with user attribution
Monitor outbound phishing indicators and inbound referer patterns that may indicate CSRF delivery attempts
Alert on anomalous administrator session activity, particularly requests originating from cross-origin contexts

How to Mitigate CVE-2026-57747

Immediate Actions Required

Update the Booked plugin to a patched release above version 3.0.0 as soon as the vendor publishes a fix
Restrict Booked plugin administrative functions to trusted users and enforce least privilege on WordPress roles
Require administrators to log out of WordPress sessions when not actively managing the site to reduce CSRF exposure

Patch Information

At the time of publication, refer to the Patchstack CVE Analysis for the latest patch status and any vendor-supplied fixes for Booked versions after 3.0.0. Apply updates through the WordPress plugin management interface once a patched version becomes available.

Workarounds

Deactivate the Booked plugin until a patched version is installed if the plugin is not business-critical
Deploy a WAF rule blocking cross-origin POST requests to Booked endpoints lacking a valid WordPress nonce
Configure the SameSite=Lax or SameSite=Strict attribute on WordPress authentication cookies to limit cross-site request delivery

bash

# Example WAF rule concept (ModSecurity) to block cross-origin requests to Booked endpoints
SecRule REQUEST_URI "@contains /wp-admin/admin-ajax.php" \
  "chain,phase:2,deny,status:403,id:1057747,msg:'Possible CSRF against Booked plugin'"
  SecRule ARGS:action "@rx ^booked_" "chain"
  SecRule REQUEST_HEADERS:Referer "!@beginsWith https://your-site.example/"