What’s Vulnerable › Vulnerabilities

CVE-2026-54548: kas: Persistent SSH Host Key Checking Disablement

• Severity: low (CVSS 3.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-26 · updated 2026-09-09
• Weakness: CWE-295

Description

kas is a setup tool for bitbake based projects. Prior to 5.4, internal SSH key setup triggered by SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE creates ~/.ssh/config when no user-specific SSH configuration exists and adds a global Host * rule containing StrictHostKeyChecking no. In kas/libcmds.py, ssh_no_host_key_check() runs without checking ctx.managed_env, so the setting persists after kas exits and affects future SSH sessions by the same local user, extending beyond the intended short-lived continuous integration environment. A later SSH connection can therefore accept an attacker-controlled host key without verification, increasing the risk of a man-in-the-middle attack that compromises session confidentiality or integrity. This issue is fixed in version 5.4.

Affected products

• siemens kas: before 5.4

References

• https://github.com/siemens/kas/commit/1c1e861c9f241ce082b86bef6bedc7da9b676294
• https://github.com/siemens/kas/releases/tag/5.4
• https://github.com/siemens/kas/security/advisories/GHSA-mv8m-v9v6-5f94

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