AP Background 3.8.1 - 3.8.2 - Missing Authorization to Authenticated (Subscriber+) Arbitrary File Upload via advParallaxBackAdminSaveSlider Function
Strategic Overview
- Status
- Unpatched
- Affected Plugin
- AP Background
- Affected Version
3.8.1 – 3.8.2- CVSS
- 8.8High
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2025-9561
At a glance
CVE-2025-9561 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the AP Background WordPress plugin, affecting versions 3.8.1 – 3.8.2. 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. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed October 2025, reported by kr0d.
Vulnerability Overview
The AP Background plugin for WordPress is vulnerable to arbitrary file uploads due to missing authorization and insufficient file validation within the advParallaxBackAdminSaveSlider() handler in versions 3.8.1 to 3.8.2. This makes it possible for authenticated attackers, with Subscriber-level access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible.
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
AP Background 3.8.1 – 3.8.2 carries this weakness at advParallaxBackAdminSaveSlider(), and reaching it 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. No fixed build of this plugin is recorded for AP Background yet, so installs running 3.8.1 – 3.8.2 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?
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. 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
Related records
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