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OpenAdvisories
High · 8.5 CVE-2026-73248 EUVD-2026-57014

calibre: Bypass of Python template restrictions via nested `template()` leading to RCE

Published Aug 11, 2026 · Updated Aug 12, 2026 · Assigned by GitHub_M

Description

calibre is an e-book manager. Prior to 9.12.0, calibre processes attacker-controlled composite_template metadata from a malicious EPUB, OPF, PDF, or similar file through program: and a nested template() call whose formatter does not inherit allow_python_templates=False, allowing a nested python: template to reach compile_python_template and execute arbitrary Python code when the file is opened or imported. This issue is fixed in version 9.12.0.

Affected products

VendorProductAffectedFixed
kovidgoyal calibre < 9.12.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 calibre 9.12.0+ds+~0.10.6-1 —
Debian 13 calibre No fix yet —
Debian 12 calibre No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 calibre No fix yet —
Ubuntu 26.04 LTS calibre No fix yet —
Ubuntu 24.04 LTS calibre No fix yet —
Ubuntu 22.04 LTS calibre No fix yet —
Ubuntu 20.04 LTS calibre No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS calibre No fix yet —
Ubuntu 16.04 LTS calibre No fix yet —

References