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Fencer Vulns
high 7.4

CVE-2026-20844 json

Windows Clipboard Server Elevation of Privilege Vulnerability

published 2026-01-13 9 mo ago modified 2026-07-30 3 mo ago also EUVD-2026-2172

cvss
7.4
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

Use after free in Windows Clipboard Server allows an unauthorized attacker to elevate privileges locally.

Patch / fix

  • Microsoft Windows 10 Version 1607 10.0.14393.8783
  • Microsoft Windows 10 Version 1809 10.0.17763.8276
  • Microsoft Windows 10 Version 21H2 10.0.19044.6809
  • Microsoft Windows 10 Version 22H2 10.0.19045.6809
  • Microsoft Windows 11 version 23H2 10.0.22631.6491
  • Microsoft Windows 11 Version 24H2 10.0.26100.7623
  • Microsoft Windows 11 Version 25H2 10.0.26200.7623
  • Microsoft Windows Server 2016 10.0.14393.8783
  • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.8783
  • Microsoft Windows Server 2019 10.0.17763.8276
  • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.8276
  • Microsoft Windows Server 2022 10.0.20348.4648
  • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2092
  • Microsoft Windows Server 2025 10.0.26100.32230
  • Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.32230

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
9 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).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA 3.1 7.4 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Microsoft Windows 10 Version 1607
  • Microsoft Windows 10 Version 1809
  • Microsoft Windows 10 Version 21H2
  • Microsoft Windows 10 Version 22H2
  • Microsoft Windows 11 version 23H2
  • Microsoft Windows 11 Version 24H2
  • Microsoft Windows 11 Version 25H2
  • Microsoft Windows Server 2016
  • Microsoft Windows Server 2016 (Server Core installation)
  • Microsoft Windows Server 2019
  • Microsoft Windows Server 2019 (Server Core installation)
  • Microsoft Windows Server 2022
  • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation)
  • Microsoft Windows Server 2025
  • Microsoft Windows Server 2025 (Server Core installation)

Classification

Weakness
  • CWE-416 Use After Free
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

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.