CVE-2025-47635: WebinarPress SSRF Vulnerability

CVE-2025-47635 Overview

CVE-2025-47635 is a Server-Side Request Forgery (SSRF) vulnerability discovered in the WebinarPress WordPress plugin. This flaw allows attackers to abuse server-side functionality to make arbitrary HTTP requests from the affected WordPress server to internal or external systems. SSRF vulnerabilities are particularly dangerous as they can enable attackers to bypass firewalls, access internal services, and potentially pivot to other systems within the network.

Critical Impact

Unauthenticated attackers can exploit this SSRF vulnerability to make arbitrary server-side requests, potentially accessing internal network resources, cloud metadata services, and sensitive data that should not be publicly accessible.

Affected Products

• WebinarPress WordPress plugin versions up to and including 1.33.27
• WordPress installations running vulnerable WebinarPress versions
• Websites using WebinarPress for webinar functionality

Discovery Timeline

• 2025-05-07 - CVE-2025-47635 published to NVD
• 2025-05-12 - Last updated in NVD database

Technical Details for CVE-2025-47635

Vulnerability Analysis

This Server-Side Request Forgery vulnerability exists in the WebinarPress WordPress plugin, which is designed to provide webinar functionality to WordPress websites. The plugin fails to properly validate and sanitize user-supplied URLs before making server-side HTTP requests. This allows an unauthenticated attacker to manipulate the server into making requests to arbitrary destinations, including internal network resources that are not directly accessible from the public internet.

The vulnerability is classified under CWE-918 (Server-Side Request Forgery), which describes flaws where an attacker can craft requests that originate from the vulnerable server. This effectively allows the attacker to use the WordPress server as a proxy to reach internal services, cloud metadata endpoints, or other protected resources.

Root Cause

The root cause of CVE-2025-47635 is insufficient input validation when the WebinarPress plugin processes user-controlled URL parameters. The plugin accepts URL input from users and makes HTTP requests without properly validating that the destination is a legitimate external resource. This lack of URL validation and allowlist checking enables attackers to specify internal IP addresses, localhost references, or cloud metadata service URLs.

Attack Vector

The attack vector for this vulnerability is network-based and requires no authentication or user interaction. An attacker can exploit this flaw by sending specially crafted requests to the vulnerable WordPress site. The exploitation typically follows this pattern:

1. The attacker identifies a WebinarPress endpoint that accepts URL parameters
2. The attacker crafts a malicious request with an internal URL (e.g., http://169.254.169.254/latest/meta-data/ for AWS metadata, or http://localhost:8080/admin)
3. The WordPress server processes the request and makes a server-side HTTP call to the attacker-specified URL
4. The response from the internal resource is returned to the attacker or can be exfiltrated through other means

This SSRF vulnerability can be leveraged to scan internal networks, access cloud metadata services to steal credentials, interact with internal APIs, or bypass IP-based access controls on internal services.

Detection Methods for CVE-2025-47635

Indicators of Compromise

• Unusual outbound HTTP requests from the WordPress server to internal IP ranges (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)
• Server requests to cloud metadata endpoints such as 169.254.169.254
• WebinarPress-related endpoints receiving requests with suspicious URL parameters pointing to internal resources
• Unexpected connections from the web server to internal services or databases

Detection Strategies

• Monitor web server logs for WebinarPress endpoint requests containing internal IP addresses or localhost references
• Implement network-level monitoring for outbound connections from web servers to internal network ranges
• Deploy Web Application Firewall (WAF) rules to detect and block SSRF patterns in request parameters
• Enable logging on internal services to detect unexpected connection attempts from the WordPress server

Monitoring Recommendations

• Configure alerts for outbound traffic from the WordPress server to RFC 1918 private address ranges
• Monitor DNS queries from the web server for internal hostnames or suspicious rebinding patterns
• Review WebinarPress plugin logs for unusual activity or error messages related to HTTP requests
• Implement network segmentation and monitor for east-west traffic anomalies originating from web server segments

How to Mitigate CVE-2025-47635

Immediate Actions Required

• Update WebinarPress plugin to a version newer than 1.33.27 that addresses this vulnerability
• Temporarily disable the WebinarPress plugin if an update is not immediately available
• Implement WAF rules to block SSRF patterns targeting the WebinarPress plugin endpoints
• Review access logs for evidence of exploitation attempts

Patch Information

Site administrators should update the WebinarPress WordPress plugin to the latest available version that addresses this SSRF vulnerability. The vulnerability affects all versions from the initial release through version 1.33.27. For detailed patch information and vulnerability analysis, refer to the Patchstack SSRF Vulnerability Advisory.

Workarounds

• Disable the WebinarPress plugin until an update can be applied
• Implement egress filtering on the WordPress server to block outbound connections to internal network ranges
• Configure cloud instance metadata service protections (IMDSv2 for AWS) to limit metadata access
• Use a Web Application Firewall with SSRF detection capabilities to block malicious requests

# Example: Block outbound connections to internal ranges using iptables
# WARNING: Test thoroughly before applying to production

# Block connections to private IPv4 ranges from web server
iptables -A OUTPUT -d 10.0.0.0/8 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 172.16.0.0/12 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 192.168.0.0/16 -m owner --uid-owner www-data -j DROP
iptables -A OUTPUT -d 169.254.169.254 -m owner --uid-owner www-data -j DROP