TLS session compromise via SHA-1 certificate pins
Published Jun 25, 2025 · Updated Jun 25, 2025
Weak certificate pinning in Cyberduck 9.1.6 and earlier and Mountain Duck 4.17.5 and earlier allows man-in-the-middle attackers to alter TLS traffic. When a user permanently accepts an untrusted certificate, the clients write only its SHA-1 fingerprint to configuration and later use that weak digest as the pin. An attacker positioned on the connection must produce a colliding certificate; a successful match exposes the encrypted session's confidentiality and integrity without interrupting service.
Summary
What happened
Weak certificate pinning in Cyberduck 9.1.6 and earlier and Mountain Duck 4.17.5 and earlier allows man-in-the-middle attackers to alter TLS traffic. When a user permanently accepts an untrusted certificate, the clients write only its SHA-1 fingerprint to configuration and later use that weak digest as the pin. An attacker positioned on the connection must produce a colliding certificate; a successful match exposes the encrypted session's confidentiality and integrity without interrupting service.
The record
- CVE
- CVE-2025-41256
- Published
- Jun 25, 2025
- Updated
- Jun 25, 2025
- Vendor
- iterate GmbH
- Product
- Mountain Duck
- Classifications
- CWE-328, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 25, 2025CVE publishedPublication date reported by the CVE source.
- Jun 25, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=4.17.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- SBA certificate-pinning proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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