CVE-2026-45322

Technical summary

CVE-2026-45322 is an OS command injection vulnerability (CWE-78) in Microsoft UFO versions up to v3.0.0. The vulnerability exists in ShellReceiver.run_shell() and ShellReceiver.execute_command(), which pass action parameters directly to subprocess.Popen() with shell=True and executable=powershell.exe. Action classes including RunShellCommand.execute() and ExecuteCommand.execute() invoke the vulnerable shell receiver by forwarding stored action parameters. Because UFO persists planned and executed actions in per-session JSON files, an attacker who can modify these JSON records can inject arbitrary PowerShell commands. Upon session resumption or replay, UFO executes the injected command in the context of the UFO process user without sanitization or validation.

Business impact

This vulnerability enables local privilege escalation and unauthorized code execution on systems running UFO. The risk is elevated in multi-user or shared automation environments where session files may be accessible to lower-privileged users, or in scenarios where session data is transferred between systems. Compromised UFO sessions could lead to data exfiltration, lateral movement, system compromise, or disruption of critical automation workflows. Organizations using UFO in security-sensitive contexts should treat this as a priority remediation item.

Affected systems

Microsoft UFO open-source framework versions up to and including v3.0.0 are affected. The vulnerability is present in the shell action replay mechanism and affects any deployment that uses shell-based actions (RunShellCommand or ExecuteCommand) and stores session files on accessible storage. Systems where UFO is deployed with elevated privileges or in shared environments face the highest risk.

Exploitability

Exploitability requires local write access to UFO session JSON files. The attack vector is local (AV:L) and requires low privilege (PR:L) but no user interaction (UI:N). Once an attacker plants a malicious shell action in a session file, exploitation occurs automatically when that session is replayed—no additional steps or social engineering needed. The barrier to exploitation is moderate: an attacker must identify and gain write permissions to session storage, but the resulting command execution is reliable and direct.

Remediation

Upgrade Microsoft UFO to a version that addresses this vulnerability once available. As an interim measure, restrict write access to UFO session directories and files to authorized processes and users only. Implement file integrity monitoring on session storage to detect unauthorized modifications. Audit existing session files for suspicious shell commands. Consider isolating UFO processes with the principle of least privilege and running them in restricted service accounts. Review logs for evidence of unexpected session replays or shell command execution.

Patch guidance

Verify against the Microsoft UFO project repository and advisories for patched versions released after v3.0.0. Apply patches as soon as they become available. Before patching, ensure session files are backed up and isolated from untrusted users. After patching, perform a full test of session replay functionality to confirm the fix does not introduce regressions in automation workflows.

Detection guidance

Monitor UFO process creation and subprocess execution, particularly PowerShell invocations spawned by UFO. Audit UFO session JSON files for unexpected shell commands or suspicious command syntax (e.g., obfuscated PowerShell, Base64-encoded payloads, external command downloads). Log all modifications to session storage and correlate with UFO execution events. Watch for sessions being replayed outside normal automation schedules. Implement file integrity checks on session directories to alert on unauthorized changes.

Why prioritize this

HIGH severity (CVSS 7.8) due to high impact across confidentiality, integrity, and availability. Local attack vector and low privilege requirement make it feasible in multi-user systems. The automatic execution upon session replay means no sophisticated attacker skill is required. Organizations should prioritize patching, especially those using UFO for critical or privileged operations, or where session files may be shared or stored in less-protected locations.

Risk score, explained

CVSS 3.1 score of 7.8 reflects high impact (C:H, I:H, A:H) constrained by local-only attack vector (AV:L) and requirement for low privilege (PR:L). The lack of user interaction (UI:N) and unchanged scope (S:U) distinguish this from lower-scoring injection flaws. The score appropriately reflects that while exploitation requires local access, the consequences for affected systems are severe.

Frequently asked questions