CVE-2026-5718 | Drag and Drop Multiple File Upload for Contact Form 7 <= 1.3.9.7 - Unauthenticated Arbitrary File Upload via Non-ASCII Filename Blacklist Bypass

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).

Published: 2026-04-17 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-5718 is rated Moderate Risk (63.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.03%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-5718

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 4.25% 4.03% -0.22%
2 2026-05-27 3.17% 4.25% +1.08%
3 2026-05-22 3.17%

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-5718

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.2 5.9 [email protected]

Weakness enumeration for CVE-2026-5718

GitHub Security Advisory for CVE-2026-5718

GHSA-xj7v-jqv6-v48w · Severity: high — The Drag and Drop Multiple File Upload for Contact Form 7 plugin for WordPress is vulnerable to...

Affected software / configurations for CVE-2026-5718

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-5718

URL Tags
https://plugins.trac.wordpress.org/browser/drag-and-drop-multiple-file-upload-contact-form-7/tags/1.3.9.6/inc/dnd-upload-cf7.php#L62
https://plugins.trac.wordpress.org/browser/drag-and-drop-multiple-file-upload-contact-form-7/tags/1.3.9.6/inc/dnd-upload-cf7.php#L883
https://plugins.trac.wordpress.org/browser/drag-and-drop-multiple-file-upload-contact-form-7/tags/1.3.9.6/inc/dnd-upload-cf7.php#L970
https://plugins.trac.wordpress.org/browser/drag-and-drop-multiple-file-upload-contact-form-7/tags/1.3.9.6/inc/dnd-upload-cf7.php#L987
https://plugins.trac.wordpress.org/changeset/3508522/drag-and-drop-multiple-file-upload-contact-form-7
https://plugins.trac.wordpress.org/changeset/3548901/
https://www.wordfence.com/threat-intel/vulnerabilities/id/38f95d40-a6d4-429c-9872-9d2531e942eb?source=cve
cvelogic Threat Intelligence