Medium 6.5Published Jul 16, 2026

CVE-2026-55440Microsoft UFO: COMMAND_RESULTS handler creates unowned sessions, allowing authenticated session-squatting denial of service

Updated under an hour ago (Oct 27, 2026, 1:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-862
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jul 16, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

microsoft UFO microsoft:ufo (from the name)	before 3.0.7	CNA record

References

References

https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf	x-refsource-confirm
https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948	x-refsource-misc
https://github.com/microsoft/UFO/releases/tag/3.0.7	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.