CVE-2025-39404: Sassy Social Share Open Redirect Flaw

CVE-2025-39404 Overview

CVE-2025-39404 is an Open Redirect vulnerability [CWE-601] affecting the Heateor Sassy Social Share plugin for WordPress. The flaw exists in all versions up to and including 3.3.73. Attackers can craft malicious URLs that leverage the trusted domain of a vulnerable WordPress site to redirect victims to attacker-controlled destinations. This behavior enables phishing campaigns and credential theft by exploiting user trust in the legitimate site's domain. The vulnerability requires user interaction, such as clicking a crafted link, but does not require authentication.

Critical Impact
Attackers can abuse the plugin's URL handling to redirect users from a trusted WordPress site to phishing pages, facilitating credential theft and malware delivery.

Affected Products

Heateor Sassy Social Share plugin for WordPress
Versions from n/a through 3.3.73
WordPress sites with the sassy-social-share plugin installed and active

Discovery Timeline

2025-04-24 - CVE-2025-39404 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-39404

Vulnerability Analysis

The vulnerability resides in the Sassy Social Share plugin's URL handling logic. The plugin accepts a user-controlled URL parameter and issues an HTTP redirect without validating whether the destination points to an approved domain. This missing validation allows arbitrary external destinations to be reached through a link that appears to originate from the trusted WordPress site.

Open redirects are frequently paired with phishing kits. A victim receives a link on the legitimate domain, trusts the hostname displayed in the browser, and follows the redirect to an attacker-hosted page mimicking a login form. The scope-changed impact reflects that a trusted origin is used to hand off users to an untrusted destination.

The vulnerability does not permit code execution or direct data modification on the WordPress server. Impact is limited to confidentiality loss through social engineering. However, sites with large user bases or e-commerce functionality face elevated risk because attackers can weaponize the trusted brand for targeted phishing.

Root Cause

The root cause is improper validation of a redirect target parameter within the plugin. The code passes attacker-controlled input to a redirect function without enforcing an allowlist of permitted hosts or verifying that the target is a relative path on the same origin.

Attack Vector

An unauthenticated attacker crafts a URL on the vulnerable WordPress site that embeds an external destination in the vulnerable parameter. The attacker distributes the link through email, chat, or social media. When a victim clicks the link, the plugin issues a redirect to the attacker-controlled site, where credential harvesting or malware delivery occurs.

The vulnerability mechanism is described in the Patchstack Vulnerability Report. No public proof-of-concept exploitation code is currently available.

Detection Methods for CVE-2025-39404

Indicators of Compromise

Web server access logs showing requests to Sassy Social Share endpoints with external URLs in query parameters
HTTP 301 or 302 responses from the WordPress site redirecting to unfamiliar external domains
Referrer headers on external phishing sites pointing back to the affected WordPress installation

Detection Strategies

Inspect web server logs for requests containing URL-encoded external hostnames in plugin parameters
Deploy web application firewall rules that flag redirect parameters containing fully qualified external URLs
Correlate outbound redirects from the WordPress domain against threat intelligence feeds of known phishing infrastructure

Monitoring Recommendations

Enable verbose access logging on WordPress and monitor for anomalous query strings targeting the sassy-social-share plugin paths
Alert on user-reported phishing emails referencing links from the WordPress domain
Track redirect response codes from plugin endpoints and baseline expected destinations

How to Mitigate CVE-2025-39404

Immediate Actions Required

Update the Sassy Social Share plugin to a version later than 3.3.73 once the vendor publishes a fix
Audit WordPress plugin inventory and remove Sassy Social Share if it is not actively used
Educate users to verify final destination URLs after clicking links, especially those requesting credentials

Patch Information

At the time of publication, the vulnerability affects Sassy Social Share versions up to and including 3.3.73. Administrators should monitor the Patchstack Vulnerability Report and the plugin's official WordPress repository page for a patched release and apply it as soon as available.

Workarounds

Deactivate the Sassy Social Share plugin until a patched version is released
Configure a web application firewall to block requests where redirect parameters contain external hostnames
Restrict redirect destinations at the reverse proxy layer by rewriting or dropping outbound redirects to non-approved domains

bash

# Example WAF rule concept (ModSecurity) to block external redirect targets
SecRule ARGS "@rx ^https?://(?!yourdomain\.com)" \
    "id:1039404,phase:2,deny,status:403,msg:'Blocked external redirect target (CVE-2025-39404)'"