CVE-2026-42641: Share This Image Plugin SSRF Vulnerability

CVE-2026-42641 Overview

CVE-2026-42641 is a Server-Side Request Forgery (SSRF) vulnerability affecting the ILLID Share This Image WordPress plugin. The flaw exists in all versions up to and including 2.14. An unauthenticated attacker can coerce the vulnerable WordPress instance to issue arbitrary outbound HTTP requests on the attacker's behalf. The issue is tracked under CWE-918: Server-Side Request Forgery.

Critical Impact

Attackers can abuse the vulnerable plugin to pivot requests through the WordPress server, potentially reaching internal services, cloud metadata endpoints, or other resources not exposed to the public internet.

Affected Products

• ILLID Share This Image WordPress plugin versions through 2.14
• WordPress installations with the share-this-image plugin enabled
• Sites that have not applied vendor remediation after the disclosure date

Discovery Timeline

• 2026-04-29 - CVE-2026-42641 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-42641

Vulnerability Analysis

The Share This Image plugin provides image-sharing functionality that fetches remote image resources via server-side HTTP requests. The plugin accepts user-supplied URL input and dispatches outbound requests without enforcing destination validation. Attackers supply crafted URLs targeting internal hosts, loopback addresses, or cloud provider metadata services. The WordPress server then issues those requests using its own network position and identity.

The attack complexity is elevated because exploitation depends on knowledge of internal network topology or reachable internal endpoints. Successful exploitation crosses a security boundary, allowing attackers to interact with services that trust traffic originating from the WordPress host. The confidentiality and integrity impacts remain limited, as the attacker receives indirect responses rather than full read or write primitives.

Root Cause

The root cause is missing or insufficient validation of URL parameters before they are passed to the server-side HTTP request handler. The plugin does not enforce an allowlist of permitted schemes or destination hosts. It also does not block requests to private IP ranges such as 127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, or link-local addresses including 169.254.169.254 used by cloud metadata services.

Attack Vector

Exploitation occurs over the network without authentication or user interaction. An attacker sends a crafted HTTP request to the plugin endpoint with a malicious URL parameter pointing at an internal target. The plugin retrieves the URL server-side and may return content, headers, or error timing that discloses information about internal infrastructure. Refer to the Patchstack advisory for technical details.

Detection Methods for CVE-2026-42641

Indicators of Compromise

• Outbound HTTP requests from the WordPress server to internal IP ranges or cloud metadata endpoints such as 169.254.169.254
• Web server access logs showing repeated requests to share-this-image plugin endpoints with URL parameters referencing private or loopback addresses
• Anomalous outbound connections originating from the PHP worker process tied to WordPress

Detection Strategies

• Inspect WordPress and reverse-proxy access logs for requests targeting the share-this-image plugin paths with externally supplied URL parameters
• Correlate inbound plugin requests with outbound network connections from the PHP-FPM or Apache worker to detect SSRF pivot attempts
• Apply web application firewall rules that flag URL parameters containing private CIDR ranges, localhost, or cloud metadata hostnames

Monitoring Recommendations

• Enable egress filtering and log all outbound HTTP traffic from web tier hosts for review
• Alert on any web server initiating connections to internal management interfaces or metadata services
• Track plugin version inventory across WordPress fleets and flag installations running share-this-image 2.14 or earlier

How to Mitigate CVE-2026-42641

Immediate Actions Required

• Deactivate the Share This Image plugin until a vendor-patched version is installed
• Restrict outbound traffic from WordPress hosts to only the destinations required for normal operation
• Block access from web tier hosts to cloud metadata endpoints using IMDSv2 enforcement or network policy

Patch Information

At the time of publication, the Patchstack advisory identifies versions through 2.14 as affected. Administrators should monitor the plugin repository for a fixed release and upgrade as soon as one becomes available.

Workarounds

• Configure a web application firewall rule that rejects requests to plugin endpoints containing URL parameters referencing private IP ranges or file:// schemes
• Apply host-level egress controls that deny outbound traffic from the WordPress server to RFC1918 addresses and 169.254.169.254
• Remove the plugin entirely if image-sharing functionality is not required

# Configuration example: iptables egress restriction for WordPress host
iptables -A OUTPUT -d 169.254.169.254 -j REJECT
iptables -A OUTPUT -d 10.0.0.0/8 -p tcp --dport 80 -j REJECT
iptables -A OUTPUT -d 192.168.0.0/16 -p tcp --dport 80 -j REJECT
iptables -A OUTPUT -d 127.0.0.0/8 ! -o lo -j REJECT