Strategic Overview
- Status
- Unpatched
- Affected Plugin
- N5 Upload Form
- Affected Version
<= 1.0- CVSS
- 9.8Critical
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2021-24223
At a glance
CVE-2021-24223 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the N5 Upload Form WordPress plugin, affecting versions <= 1.0. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed March 2021, reported by Jin Huang.
Vulnerability Overview
The N5 Upload Form WordPress plugin through 1.0 suffers from an arbitrary file upload issue in page where a Form from the plugin is embed, as any file can be uploaded. The uploaded filename might be hard to guess as it's generated with md5(uniqid(rand())), however, in the case of misconfigured servers with Directory listing enabled, accessing it is trivial.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, 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
N5 Upload Form <= 1.0 carries this weakness at rand(), and reaching it 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. No fixed build of this plugin is recorded for N5 Upload Form yet, so installs running <= 1.0 stay exposed until the vendor ships one.
Remediation
No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
How does WordSec protect against this?
The attempt arrives as an ordinary request to N5 Upload Form: 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. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.
- Firewall
- Scanner
- Alerts
External References
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