CVE-2021-47937 E107 CVE debrief

Who should care

Administrators and security teams running e107 CMS 2.3.0, especially environments that grant non-admin users theme installation rights or expose administrative upload functionality to the network. Incident responders should also care if e107 is internet-facing or if there are signs of unusual theme uploads or web-shell activity.

Technical summary

The vulnerability is a file-upload-to-RCE path in e107 CMS 2.3.0. According to the supplied description, authenticated users with theme installation permissions can submit a malicious theme package via theme.php. The uploaded content can deploy a web shell into the e107_themes directory and then execute commands through payload.php. NVD metadata associates the issue with CWE-434 (Unrestricted Upload of File with Dangerous Type) and a CVSS 4.0 vector indicating network attack, low privileges, and high impact to confidentiality, integrity, and availability.

Defensive priority

High. This is an authenticated remote code execution issue with direct system command execution potential, so it merits prompt patching, permission review, and web-access monitoring.

Recommended defensive actions

• Upgrade e107 CMS to a version that addresses the issue as soon as a vendor fix is available.
• Restrict theme installation permissions to the smallest possible administrative group.
• Review access to theme.php and related upload endpoints; ensure they are not exposed beyond trusted administrative use.
• Inspect e107_themes for unexpected files, uploaded packages, or web-shell indicators.
• Check for suspicious use of payload.php or other command-execution artifacts in web logs and application logs.
• If compromise is suspected, rotate credentials used by the e107 instance and review host integrity, persistence, and outbound connections.
• Use the official e107 download and project pages to verify the current fixed release and vendor guidance.

Evidence notes

This debrief is based only on the supplied CVE record and NVD-enriched metadata. The core facts used here come from the CVE description, which states that e107 CMS 2.3.0 allows authenticated users with theme installation permissions to upload malicious theme files through theme.php and execute commands via payload.php. NVD metadata in the supplied corpus classifies the weakness as CWE-434 and lists the record as received with a high-severity CVSS 4.0 vector. No exploit steps or unsupported claims are included.

Official resources