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Fencer Vulns
medium 6.3

CVE-2026-46416 json

Microsoft UFO shared WebSocket handler state causes cross-client response hijacking

published 2026-05-27 5 mo ago modified 2026-10-26 14 d ago also EUVD-2026-32676

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

Microsoft UFO open-source framework for intelligent automation across devices and platforms. In 3.0.1-4-ge2626659, Microsoft UFO creates one shared UFOWebSocketHandler instance and reuses it for multiple authenticated WebSocket connections. The handler stores per-connection protocol objects in mutable instance fields. Each new WebSocket connection overwrites those fields. Later, message handlers send responses through the shared fields instead of through protocol objects bound to the originating connection. As a result, the most recently connected authenticated client can receive protocol responses that belong to another authenticated client.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/microsoft/UFO/security/advisories/GHSA-cwwh-p9rv-4pj4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Affected products

  • microsoft UFO

Classification

Weakness
  • CWE-284 Improper Access Control
  • CWE-488 Exposure of Data Element to Wrong Session

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.