CVE-2026-73248
calibre: Bypass of Python template restrictions via nested `template()` leading to RCE
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.
INFO
Published Date :
Aug. 11, 2026, 10:19 p.m.
Last Modified :
Aug. 11, 2026, 10:19 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-73248
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Calibre to version 9.12.0 or later.
- Avoid opening or importing untrusted files.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-73248.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-73248 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-73248
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-73248 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-73248 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Aug. 11, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'kovidgoyal', 'product': 'calibre', 'versions': [{'status': 'affected', 'version': '< 9.12.0'}]}] Added 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. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-94 Added CWE CWE-95 Added Reference https://github.com/kovidgoyal/calibre/commit/dac9990458374a81a5372a768bba6527d965aac8 Added Reference https://github.com/kovidgoyal/calibre/releases/tag/v9.12.0 Added Reference https://github.com/kovidgoyal/calibre/security/advisories/GHSA-4f7g-rjfp-hmvx