CVE-2026-4853

Description

The JetBackup – Backup, Restore & Migrate plugin for WordPress is vulnerable to Path Traversal leading to Arbitrary Directory Deletion in versions up to and including 3.1.19.8. This is due to insufficient input validation on the fileName parameter in the file upload handler. The plugin sanitizes the fileName parameter using sanitize_text_field(), which removes HTML tags but does not prevent path traversal sequences like '../'. The unsanitized filename is then directly concatenated in Upload::getFileLocation() without using basename() or validating the resolved path stays within the intended directory. When an invalid file is uploaded, the cleanup logic calls dirname() on the traversed path and passes it to Util::rm(), which recursively deletes the entire resolved directory. This makes it possible for authenticated attackers with administrator-level access to traverse outside the intended upload directory and trigger deletion of critical WordPress directories such as wp-content/plugins, effectively disabling all installed plugins and causing severe site disruption.

CVSS v3.1 Score

4.9

MEDIUM

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

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.07%

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-22 Path Traversal

References

Other References

https://plugins.trac.wordpress.org/browser/backup/tags/3.1.17.5/src/JetBackup/Ajax/Calls/AddToQueue.php#L244 https://plugins.trac.wordpress.org/browser/backup/tags/3.1.17.5/src/JetBackup/Ajax/Calls/AddToQueue.php#L64 https://plugins.trac.wordpress.org/browser/backup/tags/3.1.17.5/src/JetBackup/Upload/Upload.php#L66 https://plugins.trac.wordpress.org/browser/backup/trunk/src/JetBackup/Ajax/Calls/AddToQueue.php#L244 https://plugins.trac.wordpress.org/browser/backup/trunk/src/JetBackup/Ajax/Calls/AddToQueue.php#L64 https://plugins.trac.wordpress.org/browser/backup/trunk/src/JetBackup/Upload/Upload.php#L66 https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3495633%40backup&new=3495633%40backup&sfp_email=&sfph_mail= https://www.wordfence.com/threat-intel/vulnerabilities/id/4aa0fa80-05dd-4fe1-b7b5-7ed0cf13053c?source=cve

Frequently Asked Questions

What is CVE-2026-4853? +

The JetBackup – Backup, Restore & Migrate plugin for WordPress is vulnerable to Path Traversal leading to Arbitrary Directory Deletion in versions up to and including 3.1.19.8. This is due to insufficient input validation on the fileName parameter in the file upload handler. The plugin sanitizes the fileName parameter using sanitize_text_field(), which removes HTML tags but does not prevent path traversal sequences like '../'. The unsanitized filename is then directly concatenated in Upload::getFileLocation() without using basename() or validating the resolved path stays within the intended directory. When an invalid file is uploaded, the cleanup logic calls dirname() on the traversed path and passes it to Util::rm(), which recursively deletes the entire resolved directory. This makes it possible for authenticated attackers with administrator-level access to traverse outside the intended upload directory and trigger deletion of critical WordPress directories such as wp-content/plugins, effectively disabling all installed plugins and causing severe site disruption. It has a CVSS v3.1 base score of 4.9 (MEDIUM).

How severe is CVE-2026-4853? +

CVE-2026-4853 has a CVSS v3.1 score of 4.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0002, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-4853? +

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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