Path Traversal in Calibre-Ebook Calibre

CVE-2026-26064

calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Versions 9.2.1 and below contain a Path Traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows, this leads to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. Function extract_pictures only checks startswith('Pictures'), and does not sanitize '..' sequences. calibre's own ZipFile.extractall() in utils/zipfile.py does sanitize '..' via _get_targetpath(), but extract_pictures() bypasses this by using manual zf.read() + open(). This issue has been fixed in version 9.3.0.

Vulnerability class: Path Traversal (Directory Traversal)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.009 (56.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-26064: held from 0.009 to 0.009.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-26064?
CVE-2026-26064 is a high-severity vulnerability in Calibre-Ebook Calibre, classified under Path Traversal. CVSS score: 8.8/10. Published 2026-02-20.
How severe is CVE-2026-26064?
High severity. CVSS v3 base score is 8.8 out of 10.