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Public proof of concept

CVE-2026-5718

A public proof of concept exists; no exploitation attested.

  • Published2026-04-17
  • WeaknessCWE-434

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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, 1.3.9.7. 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. The vulnerability was originally reported by Leonid Semenenko (lsemenenko) and partially patched in version 1.3.9.7. A bypass for the patch was separately discovered and reported by Nguyen Hung (Mitchell).

Timeline

dates in UTC
  1. 2026-04-1718:16CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-5718?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-5718?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-5718 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

read 2026-10-23 19:25 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
4 repositories, unverifiedkyukazamiqq/cve-2026-5718rootdirective-sec/CVE-2026-5718-Labxxconi/CVE-2026-5718xxconi/CVE-2026-5718-PR-V-EXPLO-T
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionnone2026-04-17
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.18.1read 2026-10-23
  • CNAweakness (CWE)CWE-434read 2026-10-23
  • FIRST EPSSEPSS score3.5 %2026-10-23
  • PoC-in-GitHubproof of concept4read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2026-04-17
Last Modified
2026-06-17
NVD status
Deferred

Frequently asked questions

What is 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, 1.3.9.7. 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. The vulnerability was originally reported by Leonid Semenenko (lsemenenko) and partially patched in version 1.3.9.7. A bypass for the patch was separately discovered and reported by Nguyen Hung (Mitchell).

Is CVE-2026-5718 actively exploited?

Active exploitation of CVE-2026-5718 has not been confirmed. Its EPSS score was 3.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-5718?

CVE-2026-5718 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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