Vulnerability in kas (CVE-2026-54548)
Summary
Vulnerability in kas (CVE-2026-54548). Risk of unauthorized operations or information disclosure. Exploitable via SSH_PRIVATE_KEY. Mitigation: upgrade to 5.4 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54548 has been found in kas.
Attackers can target a specific entry point like SSH_PRIVATE_KEY over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.3/10.
What to do: upgrade kas to 5.4 or later.
If unsure, ask your IT team or search "kas CVE-2026-54548" on the vendor's site.
CVE-2026-54548 (kas) — CWE-295 / CVSS v3 3.3
Attack vector: local
Attack surface: SSH_PRIVATE_KEY / SSH_PRIVATE_KEY_FILE
Patched: 5.4 — apply immediately
Workaround: Since kas 2.6.3, a local user's SSH configuration is only written if it didn't exist before.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-295) exists in kas. Attackers reach the vulnerable code path via SSH_PRIVATE_KEY.
Check the vendor advisory for the affected versions of kas. Attack surface: SSH_PRIVATE_KEY / SSH_PRIVATE_KEY_FILE.
Severity: Low (CVSS 3.3/10). Risk of unauthorized operations or information disclosure.
Update to 5.4.
Workaround: Since kas 2.6.3, a local user's SSH configuration is only written if it didn't exist before.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'kas' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'kas' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
kasを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Since kas 2.6.3, a local user's SSH configuration is only written if it didn't exist before.パッチが適用されるまでの応急処置として、Since kas 2.6.3, a local user's SSH configuration is only written if it didn't exist before. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade kas to 5.4ステージング環境で 5.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-54548 kas
- Ubuntu UBUNTU-CVE-2026-54548 kas