CVE-2026-18386: cssimmon wp backitup community edition Path Traversal

Vulnerability summary

CVE-2026-18386 is a medium (CVSS 4.9) Path Traversal vulnerability in cssimmon wp backitup community edition. EPSS estimates a 0.73% chance of exploitation in the next 30 days, higher than 53.4% of scored vulnerabilities.

Timeline

1. 10-09-2026
   PublishedVulnerability first disclosed.
2. 10-09-2026
   Last modifiedVulnerability information updated.

Description

The WP BackItUp Community Edition plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.1.0 via the 'backup_file' parameter parameter. This makes it possible for authenticated attackers, with administrator-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information. The basename() normalization present in the handler only executes when the traversed target path does not exist, providing no protection against reads of existing files.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')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.