CVE-2026-54548: Cert Validation Flaw (CVSS 3.3)

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.

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CVSS v3.1 Score

3.3

LOW

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0009

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

References

Other 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

Frequently Asked Questions

What is CVE-2026-54548? +

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. It has a CVSS v3.1 base score of 3.3 (LOW).

How severe is CVE-2026-54548? +

CVE-2026-54548 has a CVSS v3.1 score of 3.3 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0009, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-54548? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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