CVE-2026-18983

HIGH
Published Aug 28, 2026 Modified Aug 28, 2026 CWE-434

Description

The One User Avatar | User Profile Picture plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.5.4 via the wpua_action_process_option_update function. This is due to insufficient file type validation in wp_handle_upload() called without a MIME allow-list, with post-write validation relying on the attacker-controlled client-supplied Content-Type header rather than a server-derived type, and no cleanup of files that fail the check. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. in order to exploit this vulnerability an admin has to give subscribers permission to upload avatars. While PHP files and svg files are rejected, dxfp files are accepted.

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CVSS v3.1 Score

7.5
HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0050
Probability of exploitation
0.42%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-434 Unrestricted Upload

References

Frequently Asked Questions

What is CVE-2026-18983? +
The One User Avatar | User Profile Picture plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.5.4 via the wpua_action_process_option_update function. This is due to insufficient file type validation in wp_handle_upload() called without a MIME allow-list, with post-write validation relying on the attacker-controlled client-supplied Content-Type header rather than a server-derived type, and no cleanup of files that fail the check. This makes it possible for authenticated attackers, with subscriber-level access and above, to upload files that may be executable, which makes remote code execution possible. in order to exploit this vulnerability an admin has to give subscribers permission to upload avatars. While PHP files and svg files are rejected, dxfp files are accepted. It has a CVSS v3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-18983? +
CVE-2026-18983 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0050, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-18983? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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