backupguard JetBackup Plugin up to 3.1.19.8 on WordPress Invalid File sanitize_text_field fileName path traversal

Summaryinfo

A vulnerability was found in backupguard JetBackup Plugin up to 3.1.19.8 on WordPress. It has been rated as critical. The affected element is the function sanitize_text_field of the component Invalid File Handler. The manipulation of the argument fileName leads to path traversal. This vulnerability is documented as CVE-2026-4853. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in backupguard JetBackup Plugin up to 3.1.19.8 on WordPress. It has been rated as problematic. This issue affects the function sanitize_text_field of the component Invalid File Handler. The manipulation of the argument fileName with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality. The summary by CVE is:

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.

The weakness was released by Lukasz Sobanski. The advisory is shared at wordfence.com. The identification of this vulnerability is CVE-2026-4853 since 03/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation needs additional levels of successful authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• backupguard

Name

• JetBackup Plugin

Version

• 3.1.19.0
• 3.1.19.1
• 3.1.19.2
• 3.1.19.3
• 3.1.19.4
• 3.1.19.5
• 3.1.19.6
• 3.1.19.7
• 3.1.19.8

CPE 2.3info

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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