CVE-2026-25635: calibre-ebook calibre Path Traversal

Vulnerability summary

CVE-2026-25635 is a high (CVSS 8.6) Path Traversal vulnerability in calibre-ebook calibre. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 32.6% of scored vulnerabilities. 2 public exploits are recorded.

Timeline

1. 06-02-2026
   PublishedVulnerability first disclosed.
2. 11-02-2026
   Last modifiedVulnerability information updated.

Description

calibre is an e-book manager. Prior to 9.2.0, Calibre's CHM reader contains a path traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows (haven't tested on other OS's), this can lead to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. This vulnerability is fixed in 9.2.0.

• 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.