Cyberduck and Mountain Duck - Improper Certificate Store Handling
Cyberduck and Mountain Duck improperly handle TLS certificate pinning for untrusted certificates (e.g., self-signed), unnecessarily installing it to the Windows Certificate Store of the current user without any restrictions. This issue affects Cyberduck through 9.1.6 and Mountain Duck through 4.17.5.
- Published
- Jun 25, 2025
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 7th percentile
- CWE
- CWE-266
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 32 / 40 · 8.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · sba-research
- 8.0
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (sba-research). Independent of NVD's CPE analysis and usually ahead of it.
iterate GmbH Cyberduck
- up to and including 9.1.6affected · semver
iterate GmbH Mountain Duck
- up to and including 4.17.5affected · semver
Same product
iterate gmbh: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-41256Cyberduck and Mountain Duck - Weak Hash Algorithm for Certificate Fingerprint29Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Thomas Kostalfinder
- Andreas Bollfinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- none
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-266 · Incorrect Privilege AssignmentCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- github.com/iterate-ch/cyberduck/security/advisories/GHSA-vjjc-grpp-m655
- github.com/sbaresearch/advisories/tree/public/2025/SBA-ADV-20250325-01_Cyberduck_Mountain_Duck_Certificate_Handling
Vendor advisories and official records. Exploit/PoC links are deliberately left out.