CVE-2026-25731: kovidgoyal calibre · Template Injection
Affects kovidgoyal calibreSource CVE Database V5
Not known to be exploited · CVSS 7.8 High : upgrade to 9.2.0 soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 9.2.0
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade calibre and kovidgoyal/calibre to 9.2.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| kovidgoyalcalibre | Affected
| Fixed in
|
GitHubkovidgoyal/calibrepkg:github/kovidgoyal/calibreOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
The primary mitigation is to upgrade all calibre installations to version 9.2.0 or later, where the vulnerability is patched. Organizations should audit their usage of the --template-html and --template-html-index options to ensure that only trusted templates are used. Restrict access to systems running calibre to trusted personnel and enforce strict user permissions to prevent unauthorized template injection. Implement monitoring and alerting for unusual or unauthorized execution of calibre conversion commands, especially those involving custom templates. In environments where calibre is integrated into automated workflows, validate and sanitize all template inputs before processing. Consider isolating calibre execution in sandboxed or containerized environments to limit potential damage from exploitation. Finally, educate users about the risks of running calibre with untrusted templates and enforce policies to avoid such practices.
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.