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Fencer Intel
high 8.6

CVE-2026-25635 json

calibre has a Path Traversal Leading to Arbitrary File Write and Potential Code Execution

published 9mo ago modified 4mo ago also EUVD-2026-5596

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

calibre is an e-book manager. Prior to 9.2.0, Calibre's CHM reader contains a path traversal vulnerability that allows arbitrary file writes anywhere the user has write permissions. On Windows (haven't tested on other OS's), this can lead to Remote Code Execution by writing a payload to the Startup folder, which executes on next login. 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-2026-25635

  • calibre openSUSE Tumbleweed 9.7.0-1.1

opensuse advisories openSUSE-SU-2026:10587-1

Is CVE-2026-25635 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-25635 updated cvss 8.6

calibre: Calibre: Remote Code Execution via path traversal in CHM reader

  • 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
none
Automatable
no
Technical impact
total
Assessed
9mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/kovidgoyal/calibre/security/advisories/GHSA-32vh-whvh-9fxr referenced PoC, tagged "exploit" by a source, unverified
  • 0x5t.raptx.org https://0x5t.raptx.org/posts/calibre-chm-rce referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected products

  • kovidgoyal calibre

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel 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.