Vulnerability · Published Aug 26, 2026 · Assigned by GitHub_M
CVE-2026-54548kas: Persistent SSH Host Key Checking Disablement
Low 3.3
In plain English
A low-severity improper certificate validation in kas from siemens. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | kas | no fix listed | DEBIAN-CVE-2026-54548 |
| Debian:13 | kas | no fix listed | DEBIAN-CVE-2026-54548 |
| Debian:14 | kas | 5.4-1 | DEBIAN-CVE-2026-54548 |
| PyPI | kas | 5.4 | GHSA-mv8m-v9v6-5f94 |
| PyPI | kas | 5.4 | PYSEC-2026-3855 |
| Ubuntu:22.04:LTS | kas | no fix listed | UBUNTU-CVE-2026-54548 |
| Ubuntu:24.04:LTS | kas | no fix listed | UBUNTU-CVE-2026-54548 |
| Ubuntu:25.10 | kas | no fix listed | UBUNTU-CVE-2026-54548 |
| Ubuntu:26.04:LTS | kas | no fix listed | UBUNTU-CVE-2026-54548 |
| Ubuntu:26.10 | kas | no fix listed | UBUNTU-CVE-2026-54548 |
Affected products (as reported)
Weakness: CWE-295 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
References
- https://github.com/siemens/kas/security/advisories/GHSA-mv8m-v9v6-5f94 x_refsource_CONFIRM
- https://github.com/siemens/kas/commit/1c1e861c9f241ce082b86bef6bedc7da9b676294 x_refsource_MISC
- https://github.com/siemens/kas/releases/tag/5.4 x_refsource_MISC