High 8.5Published Aug 11, 2026

CVE-2026-73248calibre: Bypass of Python template restrictions via nested `template()` leading to RCE

Updated under an hour ago (2026-10-19 09:30 UTC)

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It affects kovidgoyal calibre. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 8.5 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-94, CWE-95
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 12, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

kovidgoyal calibre kovidgoyal:calibre (from the name)	before 9.12.0	CNA record

References

https://github.com/kovidgoyal/calibre/security/advisories/GHSA-4f7g-rjfp-hmvxx-refsource-confirm
https://github.com/kovidgoyal/calibre/commit/dac9990458374a81a5372a768bba6527d965aac8x-refsource-misc
https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.