Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-34387 is a medium-severity OS Command Injection (CWE-78) vulnerability in Fleetdm Fleet. Its CVSS base score is 5.7 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 33% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-34387 is a command injection vulnerability (CWE-78) in the software installer pipeline of Fleet, an open source device management software. It affects versions prior to 4.81.1 and has a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity due to its network accessibility, low attack complexity, and lack of required privileges or user interaction.
An unauthenticated attacker with network access to a vulnerable Fleet instance can exploit this flaw by triggering an uninstall for a specially crafted software package on managed hosts. Successful exploitation results in arbitrary code execution with root privileges on macOS and Linux hosts or SYSTEM privileges on Windows hosts, potentially enabling full compromise of the managed devices.
The Fleet security advisory at https://github.com/fleetdm/fleet/security/advisories/GHSA-7rhw-5mpv-gp4h confirms that version 4.81.1 fully patches the vulnerability, and users should upgrade to this or later versions to mitigate the issue.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16758
Vulnerability Data
Fleet is open source device management software. Prior to 4.81.1, a command injection vulnerability in Fleet's software installer pipeline allows an attacker to achieve arbitrary code execution as root (macOS/Linux) or SYSTEM (Windows) on managed hosts when an uninstall is…
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triggered for a crafted software package. Version 4.81.1 patches the issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8V15.2.5
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect command sanitization during development.
Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.
Least privilege reduces the permissions available to any process that could be subverted by injected commands.
Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.
Secure engineering principles require proper neutralization of untrusted input before command construction.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.