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Fencer Vulns
high 7.8

CVE-2026-25731 json

Calibre Affected by Arbitrary Code Execution via Server-Side Template Injection in Calibre HTML Export

published 2026-02-06 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-5573

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits
0
none known

Summary

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.

Patch / fix

  • calibre-ebook calibre 9.2.0
  • calibre Debian 12 6.13.0+repack-2+deb12u6
  • calibre Debian 13 8.5.0+ds-1+deb13u2
  • calibre Debian 14 9.2.0+ds+~0.10.5-1

debian advisories DEBIAN-CVE-2026-25731

  • calibre openSUSE Tumbleweed 9.7.0-1.1

opensuse advisories openSUSE-SU-2026:10587-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25731 updated cvss 7.8

calibre: Calibre: Arbitrary Code Execution via malicious custom template file during ebook conversion

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
9 mo ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/kovidgoyal/calibre/security/advisories/GHSA-xrh9-w7qx-3gcc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • kovidgoyal calibre

Classification

Weakness
  • CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.