CVE-2026-54548 json
kas: Persistent SSH Host Key Checking Disablement
published 2026-08-26 2 mo ago modified 2026-09-10 59 d ago also GHSA-mv8m-v9v6-5f94 , PYSEC-2026-3855 , EUVD-2026-66560
- cvss
- 3.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 1%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.3 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N |
| OSV | 3.1 | 3.3 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 3.3 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | kas | <5.4 |
5.4 |
Affected products
- siemens kas
Classification
- Weakness
-
- CWE-295 Improper Certificate Validation
References
-
github.com
/siemens/kas/commit/1c1e861c9f241ce082b86bef6bedc7da9b676294
web
-
github.com
/siemens/kas/security/advisories/GHSA-mv8m-v9v6-5f94
web
-
github.com
/siemens/kas/releases/tag/5.4
web
-
github.com
/siemens/kas
package
-
pypi.org
/project/kas
package
-
github.com
/advisories/GHSA-mv8m-v9v6-5f94
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-54548
advisory
Sources
- CVE List CVE-2026-54548
- GitHub Advisory GHSA-mv8m-v9v6-5f94
- NVD CVE-2026-54548
- OSV PYSEC-2026-3855
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