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CVE-2026-5718 - Changeset Plugin

CVE-2026-5718

The Drag and Drop Multiple File Upload for Contact Form 7 plugin for WordPress is vulnerable to arbitrary file upload in versions up to, and including, 1.3.9.6. This is due to insufficient file type validation that occurs when custom blacklist types are configured, which replaces the default dangerous extension denylist instead of merging with it, and the wpcf7_antiscript_file_name() sanitization function being bypassed for filenames containing non-ASCII characters. This makes it possible for unauthenticated attackers to upload arbitrary files, such as PHP files, to the server, which can be leveraged to achieve remote code execution.

CVE-2026-5718

HIGH CVSS 8.1 Published 2026-04-17 Updated 2026-04-22
AI Risk High (87/100) Active Exploit: No strong signal Published Exploit: No public exploit references Priority: P2 Urgent
Severity Band HIGH
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Components 3
Reference Links 6
AI Risk Engine High (87/100)
Exploitability Very High
Active Exploitation No strong signal
Published Exploit Status No public exploit references

Threat Timeline

  1. 2026-04-17 CVE published and first recorded in the threat feed.
  2. 2026-04-22 Record updated with latest vulnerability metadata.
  3. 2026-04-19 AI technical context refreshed for mitigation and impact guidance.
  4. Now Monitoring for follow-up changes, linked references, and new related CVEs.

AI Context

Machine-generated threat intelligence

AI Updated 9 days ago

AI enriched 9 days ago (2026-04-19 02:01 UTC)

Technical Summary

The Drag and Drop Multiple File Upload for Contact Form 7 plugin for WordPress is vulnerable to arbitrary file upload in versions up to, and including, 1.3.9.6. This is due to insufficient file type validation that occurs when custom blacklist types are configured, which replaces the default dangerous extension denylist instead of merging with it, and the wpcf7_antiscript_file_name() sanitization function being bypassed for filenames containing non-ASCII characters. This makes it possible for unauthenticated attackers to upload arbitrary files, such as…

Potential Impact

Severity is HIGH (CVSS 8.1). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.

Exploitability Assessment

Exploitability is assessed as Very High based on remote code execution potential, low-bar exploit prerequisites.

Primary risk drivers: remote code execution potential, low-bar exploit prerequisites

Mitigation Recommendations

Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.

Detection & Monitoring

Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.

Business Impact Lens

AI risk score 87/100 (High, Very High) with priority P2 Urgent. Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.

References

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