kas Persistently Disables SSH Host Key Checking

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-54548: 0.11% estimated exploitation activity in the next 30 days; percentile 1.38 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary kas persistently disables SSH host key checking for the invoking user when internal SSH key setup is triggered via SSHPRIVATEKEY or SSHPRIVATEKEYFILE 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 <FILLME 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…

Published by the source

26 Aug 2026, 14:18 UTC

Last modified by the source

26 Aug 2026, 14:18 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mv8m-v9v6-5f94

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# Patch Next advisory brief: CVE-2026-54548

Advisory: kas Persistently Disables SSH Host Key Checking
IDs: CVE-2026-54548, GHSA-mv8m-v9v6-5f94
Record: https://patchnext.com/advisories/cve-2026-54548 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: kas 5.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI kas: affected <= 5.3; fixed in 5.4

## Suggested inspection (read-only)
- `python -m pip show kas`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on kas.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mv8m-v9v6-5f94 (GitHub-reviewed advisory GHSA-mv8m-v9v6-5f94 lists affected ranges: PyPI kas >=0 <=5.3)

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