Man-in-the-middle exposure via persistent SSH configuration
Published Aug 26, 2026 · Updated Aug 26, 2026
Improper SSH host verification in Siemens kas 5.3 and earlier allows local users to expose later SSH sessions to man-in-the-middle attacks. When SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE is set without an existing user SSH config, ssh_no_host_key_check() writes a global Host * rule with StrictHostKeyChecking no. The local user must trigger internal key setup before man-in-the-middle attackers can impersonate a later SSH host and compromise session confidentiality or integrity.
Summary
What happened
Improper SSH host verification in Siemens kas 5.3 and earlier allows local users to expose later SSH sessions to man-in-the-middle attacks. When SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE is set without an existing user SSH config, ssh_no_host_key_check() writes a global Host * rule with StrictHostKeyChecking no. The local user must trigger internal key setup before man-in-the-middle attackers can impersonate a later SSH host and compromise session confidentiality or integrity.
The record
- CVE
- CVE-2026-54548
- Published
- Aug 26, 2026
- Updated
- Aug 26, 2026
- Vendor
- Siemens
- Product
- kas
- Classifications
- CWE-295, T1557
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 26, 2026CVE publishedPublication date reported by the CVE source.
- Aug 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 5.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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