Vulnerability · Published Aug 11, 2026 · Assigned by GitHub_M
CVE-2026-73248calibre: Bypass of Python template restrictions via nested `template()` leading to RCE
High 8.5
In plain English
A high-severity code injection in calibre from kovidgoyal. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | calibre | no fix listed | DEBIAN-CVE-2026-73248 |
| Debian:13 | calibre | no fix listed | DEBIAN-CVE-2026-73248 |
| Debian:14 | calibre | 9.12.0+ds+~0.10.6-1 | DEBIAN-CVE-2026-73248 |
| Ubuntu:22.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73248 |
| Ubuntu:24.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73248 |
| Ubuntu:26.04:LTS | calibre | no fix listed | UBUNTU-CVE-2026-73248 |
| Ubuntu:26.10 | calibre | no fix listed | UBUNTU-CVE-2026-73248 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| kovidgoyal | calibre | < 9.12.0 |
Weakness: CWE-94, CWE-95 · 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