# kas Persistently Disables SSH Host Key Checking

Advisory record · `GHSA-mv8m-v9v6-5f94`

- **Identifiers:** `GHSA-mv8m-v9v6-5f94` · `CVE-2026-54548` · `PYSEC-2026-3855`
- **State:** Confirmed
- **Severity:** CVSS 3.3 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-295](https://cwe.mitre.org/data/definitions/295.html)
- **Tags:** [Weak cryptography or TLS](https://agentprime.io/advisories/tag/weak-crypto.md)
- **Published:** 26 Aug 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 26 Aug 2026, 14:18 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `kas` (PyPI): affected `<5.4`; fixed in `5.4`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> kas versions before 5.4 persistently disable SSH host key checking for the invoking user when SSH key setup is triggered via SSH_PRIVATE_KEY or SSH_PRIVATE_KEY_FILE and no \~/.ssh/config exists. kas writes a global rule with StrictHostKeyChecking set to no, which weakens verification of SSH connections the user makes later, outside kas itself. Upgrade to kas 5.4 or later. If running an affected version, create your own \~/.ssh/config before calling kas, or remove the settings kas added to it.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 3.3 Low, CVSS 3.1: `CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0011, the 1st percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:10 UTC: First seen by agentprime
- 31 Oct 2026, 14:10 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-mv8m-v9v6-5f94)

## Sources

- [GitHub Advisory Database: GHSA-mv8m-v9v6-5f94](https://github.com/advisories/GHSA-mv8m-v9v6-5f94)
- [OSV: GHSA-mv8m-v9v6-5f94](https://osv.dev/vulnerability/GHSA-mv8m-v9v6-5f94)
- <https://github.com/siemens/kas/security/advisories/GHSA-mv8m-v9v6-5f94>
- <https://github.com/siemens/kas/commit/1c1e861c9f241ce082b86bef6bedc7da9b676294>
- <https://github.com/siemens/kas>
- <https://github.com/siemens/kas/releases/tag/5.4>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-mv8m-v9v6-5f94>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-mv8m-v9v6-5f94/>. Everything for agents: <https://agentprime.io/llms.txt>.