Contact Form 7 <= 5.3.1 - Arbitrary File Upload via Bypass
Strategic Overview
- Status
- Patched in 5.3.2
- Affected Plugin
- Contact Form 7
- Affected Version
< 5.3.2- CVSS
- 8.1High
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2020-35489
At a glance
CVE-2020-35489 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Contact Form 7 WordPress plugin, affecting versions < 5.3.2. It carries a CVSS score of 8.1 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 5.3.2; sites on affected versions should update now. Disclosed December 2020, reported by Jinson Varghese Behanan.
Vulnerability Overview
The Contact Form 7 plugin for WordPress is vulnerable to arbitrary file uploads in versions up to 5.3.2. This is due to the fact that the plugin allows filenames to contain special characters which may make extension filter evasion possible on certain configurations. Our team was not able to reproduce this issue which leads us to believe there is a high attack complexity or special configuration requirement.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, and no privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.
CWE-434: Unrestricted Upload of File with Dangerous Type
Reaching this weakness in Contact Form 7 < 5.3.2 takes a caller who can reach the endpoint. An unrestricted file upload lets a caller store a file whose type or destination the application does not properly constrain.
If an uploaded file lands anywhere the server will execute, the flaw becomes remote code execution and the site should be treated as fully compromised. For Contact Form 7 the fix is 5.3.2: builds < 5.3.2 are affected, anything from 5.3.2 onward is not.
Remediation
Update to version 5.3.2, or a newer patched version
How does WordSec protect against this?
The attempt arrives as an ordinary request to Contact Form 7: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Contact Form 7 5.3.2 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Contact Form 7
- 6.3CVE-2018-20979: Contact Form 7 <= 5.0.3 Authorization Bypass
CVE-2018-20979 - 6.1CVE-2024-4704: Contact Form 7 <= 5.9.4 Open Redirect
CVE-2024-4704 - 6.1CVE-2024-2242: Contact Form 7 <= 5.9 Reflected Cross-Site Scripting
CVE-2024-2242 - 5.3CVE-2025-3247: Contact Form 7 <= 6.0.5 Order Replay Vulnerability
CVE-2025-3247 - 5.3CVE-2014-2265: Contact Form 7 < 3.7.2 CAPTCHA Bypass
CVE-2014-2265
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C