Vulnerability in Calibre-Ebook Calibre
CVE-2026-25731
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (15.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Calibre-Ebook Calibre
- Kovidgoyal Calibre — versions < 9.2.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/kovidgoyal/calibre/security/advisories/GHSA-xrh9-w7qx-3gcc (Exploit, Third Party Advisory)
- github.com/kovidgoyal/calibre/commit/f0649b27512e987b95fcab2e1e0a3bcdafc23379 (Patch)
Frequently asked questions
- What is CVE-2026-25731?
- CVE-2026-25731 is a high-severity vulnerability in Calibre-Ebook Calibre, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 7.8/10. Published 2026-02-06.
- How severe is CVE-2026-25731?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2026-25731 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.