CVE-2026-53511 PUBLISHED

calibre: Arbitrary Code Execution in Template Formatter via Book Metadata

Assigner: GitHub_M
Reserved: 09.06.2026 Published: 07.07.2026 Updated: 08.07.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.5

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

Product Status

Vendor	kovidgoyal
Product	calibre
Versions	Version < 9.10.0 is affected

References

Problem Types

CWE-94: Improper Control of Generation of Code ('Code Injection') CWE