CVE-2026-55440 Missing authorization in UFO
Authenticated attackers can create unowned sessions to deny service to legitimate users or exhaust memory in Microsoft UFO.
- 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-2026-55440?
CVE-2026-55440 is a medium-severity missing authorization vulnerability in microsoft UFO, published on 16 Jul 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. Prior to 3.0.7, the COMMAND_RESULTS handler in ufo/server/ws/handler.py called get_or_create_session in ufo/server/services/session_manager.py without owner_client_id, allowing an authenticated client to create an unowned attacker-chosen session_id such as constellation_task_id = f"{task_name}@{task_id}" and deny the legitimate owner or exhaust memory with phantom sessions. This issue is fixed in version 3.0.7.
Which versions are affected by CVE-2026-55440?
How do I fix CVE-2026-55440?
No fix has been published for CVE-2026-55440 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-2026-55440 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55440 exists.
Sources
Also known as GHSA-hxjv-fmjf-wmjf.