OS Command Injection in github.com/fleetdm/fleet/v4 (CVE-2026-27806)
Summary
OS command injection in github.com/fleetdm/fleet/v4 (CVE-2026-27806). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 4.81.1 or later.
Original description
The description as published by the source.
Fleet is open source device management software. Prior to 4.81.1, the Orbit agent's FileVault disk encryption key rotation flow on collects a local user's password via a GUI dialog and interpolates it directly into a Tcl/expect script executed via exec.Command("expect", "-c", script). Because the password is inserted into Tcl brace-quoted send {%s}, a password containing } terminates the literal and injects arbitrary Tcl commands. Since Orbit runs as root, this allows a local unprivileged user to escalate to root privileges. This vulnerability is fixed in 4.81.1.
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-2026-27806 has been found in github.com/fleetdm/fleet/v4.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: upgrade github.com/fleetdm/fleet/v4 to 4.81.1 or later.
If unsure, ask your IT team or search "github.com/fleetdm/fleet/v4 CVE-2026-27806" on the vendor's site.
CVE-2026-27806 (github.com/fleetdm/fleet/v4) — CWE-78 / CVSS v3 7.8
Attack vector: local / no user interaction
Patched: 4.81.1 — apply immediately
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.
OS command injection (CWE-78) exists in github.com/fleetdm/fleet/v4.
Check the vendor advisory for the affected versions of github.com/fleetdm/fleet/v4.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to 4.81.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/fleetdm/fleet/v4' . 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
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1Identify exposure identify
grep -r 'github.com/fleetdm/fleet/v4' . | 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
github.com/fleetdm/fleet/v4を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/fleetdm/fleet/v4 to 4.81.1ステージング環境で 4.81.1 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。
-
3Post-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
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- web github.com