User Submitted Posts <= 20230902 - Unauthenticated Arbitrary File Upload
Strategic Overview
- Status
- Patched in 20230914
- Affected Version
<= 20230902- CVSS
- 9.8Critical
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2023-45603
At a glance
CVE-2023-45603 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the User Submitted Posts WordPress plugin, affecting versions <= 20230902. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 20230914; sites on affected versions should update now. Disclosed October 2023, reported by Rafie Muhammad.
Vulnerability Overview
The User Submitted Posts plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the usp_attach_images function in versions up to, and including, 20230902. This makes it possible for unauthenticatedattackers to upload arbitrary files as long as the extension does not contain 'php' 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 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
User Submitted Posts <= 20230902 carries this weakness at php, and reaching it takes no account at all. 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 User Submitted Posts the fix is 20230914: builds <= 20230902 are affected, anything from 20230914 onward is not.
Remediation
Update to version 20230914, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: 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: User Submitted Posts 20230914 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Login Security
External References
Related records
Same weakness class
Other vulnerabilities in User Submitted Posts – Enable Users to Submit Posts from the Front End
- 7.2CVE-2026-0800: User Submitted Posts Stored XSS
CVE-2026-0800 - 7.2CVE-2023-4308: User Submitted Posts <= 20230809 Stored XSS
CVE-2023-4308 - 7.2CVE-2016-11001: User Submitted Posts < 20160215 Reflected XSS
CVE-2016-11001 - 6.4CVE-2026-0913: User Submitted Posts <= 20260110 Stored XSS
CVE-2026-0913 - 6.4CVE-2023-7251: User Submitted Posts <= 20230901 Stored XSS
CVE-2023-7251 - 6.4CVE-2023-4779: User Submitted Posts Stored XSS
CVE-2023-4779 - 5.3CVE-2026-2126: User Submitted Posts Incorrect Authorization
CVE-2026-2126 - 5.3CVE-2025-68509: User Submitted Posts <= 20251121 Open Redirect
CVE-2025-68509
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