🛡️ CVE-2026-25731 — calibre

🟠 CVSS 7.8 — High ⚠️ Exploit Public CWE-1336 NVD

7.8

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Weakness class

CVE-2026-25731 is classified as CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when…

Affected software

CVE-2026-25731 is recorded against 1 package.

calibre (fixed in 9.2.0)

Timeline and source

Published on 6 February 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com
github.com

CVE-2026-25731 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Debian Ubuntu

Details

Severity HIGH

CVSS Score 7.8

CVSS Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE CWE-1336

Public Exploit ⚠️ Yes

Source NVD

Published 2026-02-06

Updated 2026-08-11

Modified 2026-06-17

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

Affected Packages

Software	From version	Fixed in
calibre	—	9.2.0

References

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

Exploit, Third Party Advisory https://github.com/kovidgoyal/calibre/security/advisories/GHSA-xrh9-w7qx-3gcc

🔗 NVD 🔗 Mitre ✅ Fix / Advisory

Similar Threats

Exploit Protection

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