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Fencer Intel
high 7.4

CVE-2025-41256 json

Cyberduck and Mountain Duck - Weak Hash Algorithm for Certificate Fingerprint

published last yr. modified 4mo ago also EUVD-2025-19095

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

Cyberduck and Mountain Duck improper handle TLS certificate pinning for untrusted certificates (e.g., self-signed), since the certificate fingerprint is stored as SHA-1, although SHA-1 is considered weak.

This issue affects Cyberduck: through 9.1.6; Mountain Duck: through 4.17.5.

Is CVE-2025-41256 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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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
last yr.

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/sbaresearch/advisories/tree/public/2025/SBA-ADV-20250325-02_Cyberduck_Mountain_Duck_Weak_Hash referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/iterate-ch/cyberduck/security/advisories/GHSA-688c-vjrc-84rv referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • iterate GmbH Cyberduck
  • iterate GmbH Mountain Duck

Classification

Weakness

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.