CVE-2025-30534 Overview
CVE-2025-30534 is a Cross-Site Request Forgery (CSRF) vulnerability [CWE-352] in the captcha.soft Image Captcha plugin for WordPress. The flaw affects all versions up to and including 1.2. An attacker can craft a malicious request that, when triggered by an authenticated administrator visiting an attacker-controlled page, modifies plugin settings without consent. The vulnerability requires user interaction and is exploitable over the network without authentication on the attacker side.
Critical Impact
Successful exploitation allows unauthorized modification of Image Captcha plugin settings on affected WordPress sites when an administrator is lured into triggering a forged request.
Affected Products
- captcha.soft Image Captcha plugin for WordPress
- All versions from initial release through 1.2
- WordPress sites with the Image Captcha plugin installed and active
Discovery Timeline
- 2025-03-24 - CVE-2025-30534 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-30534
Vulnerability Analysis
The Image Captcha plugin exposes state-changing settings endpoints that do not validate the origin of incoming requests. WordPress plugins typically protect administrative actions using nonce tokens generated with wp_create_nonce() and validated with check_admin_referer() or wp_verify_nonce(). The affected plugin omits or improperly implements this validation on its settings handler. As a result, any authenticated administrator's browser can be coerced into submitting a settings-change request originating from a third-party domain.
The vulnerability is limited to integrity impact. Confidentiality and availability of the WordPress instance remain unaffected by the CSRF condition itself, though attacker-controlled captcha configuration may weaken downstream form protections such as comment or registration flows.
Root Cause
The root cause is the absence of anti-CSRF token verification on the plugin's settings-processing logic. Without server-side validation of a unique per-session token bound to the requesting user, the plugin cannot distinguish legitimate administrator actions from forged submissions delivered via a cross-origin request.
Attack Vector
Exploitation requires an authenticated WordPress administrator to visit an attacker-controlled webpage or click a crafted link while their session is active. The attacker's page silently issues a POST or GET request to the vulnerable plugin settings endpoint using an auto-submitting form or image tag. The administrator's browser attaches the WordPress session cookie, and the server processes the request as legitimate. Refer to the Patchstack Vulnerability Advisory for additional technical detail.
Detection Methods for CVE-2025-30534
Indicators of Compromise
- Unexpected changes to Image Captcha plugin settings recorded in WordPress option tables such as wp_options.
- HTTP requests to plugin administrative endpoints with Referer headers pointing to external, untrusted domains.
- Administrator sessions performing settings updates within seconds of loading unrelated third-party pages.
Detection Strategies
- Review web server access logs for POST requests to /wp-admin/ endpoints associated with the Image Captcha plugin that carry off-site or missing Referer headers.
- Monitor WordPress audit logs for configuration changes to captcha settings that lack a corresponding legitimate administrator workflow.
- Deploy a Web Application Firewall (WAF) rule that flags administrative POST requests missing a valid nonce parameter.
Monitoring Recommendations
- Enable a WordPress activity logging plugin to capture user, timestamp, and IP for every settings modification.
- Alert on administrator account activity originating from unusual geolocations or user-agent strings.
- Correlate outbound browsing telemetry from administrator workstations with subsequent plugin configuration changes.
How to Mitigate CVE-2025-30534
Immediate Actions Required
- Deactivate the Image Captcha plugin on any WordPress site running version 1.2 or earlier until a patched release is available.
- Restrict access to /wp-admin/ by IP allowlist where feasible to reduce the exposure window.
- Instruct administrators to log out of WordPress sessions when not actively performing management tasks.
Patch Information
At the time of publication, the vendor advisory tracked by Patchstack indicates the vulnerability affects versions up to and including 1.2. Site owners should monitor the Patchstack Vulnerability Advisory and the WordPress plugin repository for a fixed release, and upgrade immediately once available.
Workarounds
- Replace the Image Captcha plugin with a maintained captcha solution that implements nonce validation on all settings endpoints.
- Deploy a WAF rule that blocks requests to plugin admin endpoints when the Referer header does not match the site's own domain.
- Require administrators to use a dedicated browser profile or session for WordPress management to prevent cross-site interaction with untrusted content.
# Example WAF rule enforcing same-origin Referer on WordPress admin POST requests
SecRule REQUEST_METHOD "@streq POST" \
"chain,id:1009001,phase:1,deny,status:403,msg:'CSRF: off-site admin POST blocked'"
SecRule REQUEST_URI "@beginsWith /wp-admin/" "chain"
SecRule REQUEST_HEADERS:Referer "!@beginsWith https://example.com/"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
