CVE-2026-46538 Microsoft UFO accepts cross-device TASK_END messages by session_id only, allowing peer task-result injection
An authenticated peer can inject forged task results into Microsoft UFO by spoofing session IDs, potentially compromising automation workflows.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-46538?
CVE-2026-46538 is a medium-severity missing authorization vulnerability in microsoft UFO, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Microsoft UFO open-source framework for intelligent automation across devices and platforms. In 3.0.1-4-ge2626659, Microsoft UFO's constellation client tracks pending task responses by session_id only and does not verify that a TASK_END message came from the device that originally received the task. When the constellation sends a task to a target device, it records a pending Future under a session key. The pending task record stores the expected device ID, but the completion path ignores that binding. If another authenticated peer device sends a forged TASK_END with the same session_id, the constellation accepts the response and completes the victim device's pending Future with attacker-controlled result data. This is an authenticated cross-device task-result injection issue.
Which versions are affected by CVE-2026-46538?
How do I fix CVE-2026-46538?
No fix has been published for CVE-2026-46538 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-46538 being exploited?
There is no known exploitation of CVE-2026-46538 in the wild and no public exploit code.