CVE-2026-25731: Calibre Affected by Arbitrary Code Execution via Server-Side Template Injection in Calibre HTML Export

Published Feb 6, 2026
·
Updated

calibre is an e-book manager. Prior to 9.2.0, a Server-Side Template Injection (SSTI) vulnerability in Calibre's Templite templating engine allows arbitrary code execution when a user converts an ebook using a malicious custom template file via the --template-html or --template-html-index command-line options. This vulnerability is fixed in 9.2.0.

Affected Software

2 affected components
Calibre Calibre<9.2.0
Calibre-ebook Calibre<9.2.0

Remediation

Patch Available

https://github.com/kovidgoyal/calibre/commit/f0649b27512e987b95fcab2e1e0a3bcdafc23379

Event History

Feb 6, 2026
CVE Published
via MITRE·08:14 PM
Data Sourced
via MITRE·08:14 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·09:16 PM
RemedyDescriptionSeverityWeaknessAffected Software
Feb 26, 58104
Event
via FIRST·10:47 PM
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Frequently Asked Questions

1

What is the severity of CVE-2026-25731?

CVE-2026-25731 is classified as a critical vulnerability due to its potential for arbitrary code execution.

2

How do I fix CVE-2026-25731?

To fix CVE-2026-25731, upgrade Calibre to version 9.2.0 or later.

3

What causes CVE-2026-25731 in Calibre?

CVE-2026-25731 is caused by a Server-Side Template Injection vulnerability in Calibre's Templite templating engine.

4

What versions of Calibre are affected by CVE-2026-25731?

CVE-2026-25731 affects all versions of Calibre prior to 9.2.0.

5

Can CVE-2026-25731 be exploited remotely?

Yes, CVE-2026-25731 can be exploited remotely if an attacker can trigger the vulnerable templating feature.

Company

Resources

Contact

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CVE-2026-25731 - Calibre Affected by Arbitrary Code Execution via Server-Side Template Injection in Calibre HTML Export - SecAlerts