CVE-2026-53511

calibre: Arbitrary Code Execution in Template Formatter via Book Metadata

CVSS 8.5 HIGHEPSS 0.2%CWE-94

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 8.5EPSS 0.2%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

07 Jul 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

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

Affected products

kovidgoyal · calibre

References

https://github.com/kovidgoyal/calibre/commit/712f4e1ff5c1e798c335bef3bacc4efdee052e9c https://github.com/kovidgoyal/calibre/releases/tag/v9.10.0 https://github.com/kovidgoyal/calibre/security/advisories/GHSA-2j4m-2q7x-2c47