What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-16 · updated 2026-10-24
• Weakness: CWE-400

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.

Affected products

• microsoft UFO: before 3.0.7

References

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

Get alerted when CVE-2026-55440 or the next vulnerability affects your stack