High severity · published Jul 7, 2026
CVE-2026-53511
calibre: Arbitrary Code Execution in Template Formatter via Book Metadata
8.5
CVSS
0.2%
EPSS
No
On KEV
Description
calibre is an e-book manager. Prior to 9.10.0, a malicious EPUB, OPF, or PDF file can execute arbitrary Python code when its metadata is read by calibre, including through Add books or Edit books, by embedding a custom column definition with a python: template in calibre:user_metadata that is passed unsanitized to exec() in the template formatter. This issue is fixed in version 9.10.0.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CA
calibre · kovidgoyal
< 9.10.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-53511
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-53511
github.com
https://github.com/kovidgoyal/calibre/commit/712f4e1ff5c1e798c335bef3bacc4efdee052e9c
github.com
https://github.com/kovidgoyal/calibre/releases/tag/v9.10.0
github.com
https://github.com/kovidgoyal/calibre/security/advisories/GHSA-2j4m-2q7x-2c47
lists.debian.org
https://lists.debian.org/debian-lts-announce/2026/08/msg00034.html
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