CVE-2026-30853: Calibre-Ebook Calibre

High severity, CVSS 8.2. EPSS: 0.2% chance of exploitation in the next 30 days.

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to 9.5.0, a path traversal vulnerability in the RocketBook (.rb) input plugin (src/calibre/ebooks/rb/reader.py) allows an attacker to write arbitrary files to any path writable by the calibre process when a user opens or converts a crafted .rb file. This is the same bug class fixed in CVE-2026-26065 for the PDB readers, but the fix was never applied to the RB reader. This vulnerability is fixed in 9.5.0.

Affected products

• Calibre-Ebook Calibre: before 9.5.0 (fixed in 9.5.0)

Published 2026-03-13. Last modified 2026-06-17.