CVE-2026-83526: File Upload RCE (CVSS 8.8)

Description

The FV Player 8 plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 8.1.7 via the check_mimetype function. This is due to insufficient file type validation in check_mimetype(), which writes attacker-supplied remote file content to the public uploads directory before any MIME or extension check, combined with a missing capability check on new player creation. 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. This requires successfully exploiting a race condition.

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CVSS v3.1 Score

8.8

HIGH

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

EPSS — Exploit Prediction

0.0064

Probability of exploitation

0.50%

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

Other References

Frequently Asked Questions

What is CVE-2026-83526? +

The FV Player 8 plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 8.1.7 via the check_mimetype function. This is due to insufficient file type validation in check_mimetype(), which writes attacker-supplied remote file content to the public uploads directory before any MIME or extension check, combined with a missing capability check on new player creation. 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. This requires successfully exploiting a race condition. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-83526? +

CVE-2026-83526 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0064, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-83526? +

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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