GitHub Advisoryadvisory · PyPI

GHSA-mv8m-v9v6-5f94 kas Persistently Disables SSH Host Key Checking

LOW Published 2026-08-26 Modified 2026-08-26 Official page ↗
Aliases
CVE-2026-54548
Ecosystem
PyPI
Packages
kas
Severity
Low
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N
Weaknesses
CWE-295
Reviewed
2026-08-26

Affected packages

• PyPI kas: < 5.4 → fixed in 5.4

Description

Summary kas persistently disables SSH host key checking for the invoking user when internal SSH key setup is triggered via `SSH_PRIVATE_KEY` or `SSH_PRIVATE_KEY_FILE` and no user-specific SSH configuration file exists so far. When this path is used, kas creates `~/.ssh/config` with a global `Host *` rule containing `StrictHostKeyChecking no`. This was intended to ease the use of kas in short-lived CI environments that lack a pre-configured set of known hosts. In case a local user had no SSH configuration file so far, this approach weakens SSH host authenticity verification beyond the lifetime and scope of the kas command, increasing the risk of successful man-in-the-middle attacks against future SSH connections made by the same user. Patches Such SSH configurations were created since the very first public release. The issue is addressed now by commit which is part of kas version 5.4. Workarounds Since kas 2.6.3, a local user's SSH configuration is only written if it didn't exist before. From that version on, the issue can be avoided by creating an own `~/.ssh/config` prior to calling kas. If kas was already called, `~/.ssh/config` should be inspected and undesired settings created by kas should be removed.

Related

Alias · CVE (1)

  • CVE-2026-54548 kas is a setup tool for bitbake based projects. vulnerability

Weakness · CWE (1)

  • CWE-295 Improper Certificate Validation weakness

References