AccessPress Themes and Plugin <= Various Versions - Authenticated (Subscriber+) Arbitrary File Upload
Strategic Overview
- Status
- Patched in 1.4.3
- Affected Theme
- Arrival
- Affected Version
<= 1.4.2- CVSS
- 8.8High
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2021-39317
At a glance
CVE-2021-39317 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Arrival WordPress theme, affecting versions <= 1.4.2. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 1.4.3; sites on affected versions should update now. Disclosed October 2021, reported by Chloe Chamberland.
Vulnerability Overview
A WordPress plugin and several WordPress themes developed by AccessPress Themes are vulnerable to malicious file uploads via the plugin_offline_installer AJAX action due to a missing capability check in the plugin_offline_installer_callback function found in the /demo-functions.php file or /welcome.php file of the affected products.
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 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 Arrival <= 1.4.2 takes an account at Subscriber level or above. 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 Arrival the fix is 1.4.3: builds <= 1.4.2 are affected, anything from 1.4.3 onward is not.
Remediation
Update to version 1.4.3, or a newer patched version
How does WordSec protect against this?
An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: 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: Arrival 1.4.3 closes this, and updating the theme is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
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