CVE-2024-49648: SVG Captcha Reflected XSS Vulnerability

CVE-2024-49648 Overview

CVE-2024-49648 is a reflected Cross-Site Scripting (XSS) vulnerability in the svg-captcha WordPress plugin by rafasashi. The flaw stems from improper neutralization of user-supplied input during web page generation [CWE-79]. All versions of SVG Captcha up to and including 1.0.11 are affected. Attackers can craft malicious links that execute arbitrary JavaScript in a victim's browser when clicked. Successful exploitation can lead to session theft, credential harvesting, and unauthorized actions performed in the context of the targeted user.

Critical Impact
Attackers can execute arbitrary scripts in a victim's browser, hijack authenticated sessions, and pivot to administrative actions on the affected WordPress site.

Affected Products

rafasashi SVG Captcha WordPress plugin, all versions through 1.0.11
WordPress sites with the svg-captcha plugin installed and active
Any environment exposing the vulnerable plugin endpoints to untrusted users

Discovery Timeline

2024-10-29 - CVE-2024-49648 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-49648

Vulnerability Analysis

The vulnerability is a reflected XSS issue within the SVG Captcha plugin for WordPress. The plugin reflects user-controlled input into HTTP responses without applying adequate output encoding or input sanitization. An attacker delivers a crafted URL containing a malicious payload to a victim. When the victim's browser renders the response, the injected script executes in the security context of the WordPress site. The EPSS score is approximately 0.275%, indicating low observed exploitation probability, though the technical barrier to weaponization remains low for any attacker with social engineering capability.

Root Cause

The root cause is missing or insufficient neutralization of HTML metacharacters in request parameters processed by the plugin. The plugin echoes attacker-controlled values into the response body without HTML-entity encoding or contextual escaping. This violates the secure output guidance enumerated in [CWE-79].

Attack Vector

Exploitation requires user interaction. The attacker crafts a URL pointing to a vulnerable plugin endpoint and embeds JavaScript inside a reflected parameter. The victim must click the link or visit a page that triggers the request. Because the issue produces a scope change in the CVSS vector, the injected script can affect resources beyond the immediate vulnerable component, including other site sessions and cookies accessible to the browser origin.

No verified proof-of-concept code is published in the referenced advisory. See the Patchstack advisory for additional technical context.

Detection Methods for CVE-2024-49648

Indicators of Compromise

Web server access logs containing requests to svg-captcha plugin endpoints with URL parameters embedding <script>, onerror=, javascript:, or HTML entity-encoded variants
Unexpected outbound requests from user browsers to attacker-controlled hosts referenced in plugin response bodies
Anomalous administrator session activity, including new user creation or plugin/theme installation, originating shortly after a reflected request

Detection Strategies

Inspect HTTP request logs for query strings targeting svg-captcha paths and matching XSS pattern signatures
Deploy a Web Application Firewall (WAF) rule set tuned for reflected XSS payloads against WordPress plugin endpoints
Correlate referer headers and click-through patterns from external sources with subsequent privileged actions in WordPress audit logs

Monitoring Recommendations

Enable detailed WordPress audit logging for authentication events, user role changes, and plugin modifications
Monitor Content Security Policy (CSP) violation reports for inline script execution attempts on pages served by the plugin
Track plugin version inventories across managed WordPress instances to identify hosts running svg-captcha at or below version 1.0.11

How to Mitigate CVE-2024-49648

Immediate Actions Required

Deactivate and remove the SVG Captcha plugin until a patched release is verified by the vendor
Apply WAF signatures that block reflected XSS payloads aimed at WordPress plugin parameters
Invalidate active administrator sessions and force password rotation if exploitation is suspected

Patch Information

The advisory from Patchstack lists all versions through 1.0.11 as affected. At the time of NVD publication, no fixed version is identified in the referenced sources. Review the Patchstack vulnerability database entry for the latest remediation guidance and any subsequent vendor release.

Workarounds

Replace SVG Captcha with an actively maintained CAPTCHA plugin that has a documented secure development lifecycle
Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins
Restrict access to WordPress administrative URLs by IP allow-list or VPN to reduce the impact of credential theft via reflected XSS

bash

# Example nginx CSP header to reduce reflected XSS impact
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'";
add_header X-Content-Type-Options "nosniff";
add_header Referrer-Policy "strict-origin-when-cross-origin";