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Fencer Intel
medium 6.6

CVE-2020-3427 json

Duo Authentication for Windows Logon and RDP Privilege Escalation Vulnerability

published 6y ago modified 4mo ago also EUVD-2020-24698

cvss
6.6
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 23%
public exploits
0
none known

Summary

The Windows Logon installer prior to 4.1.2 did not properly validate file installation paths. This allows an attacker with local user privileges to coerce the installer to write to arbitrary privileged directories. If successful, an attacker can manipulate files used by Windows Logon, cause Denial of Service (DoS) by deleting file(s), or replace system files to potentially achieve elevation of privileges. Note that this can only exploitable during new installations while the installer is running and is not exploitable once installation is finished. Versions 4.1.2 of Windows Logon addresses this issue.

Patch / fix

  • Cisco Duo Authentication for Windows Logon and RDP 4.1.2

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last yr.

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.6 CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 4.6 AV:L/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Cisco Duo Authentication for Windows Logon and RDP

Classification

Weakness
  • CWE-280 Improper Handling of Insufficient Permissions or Privileges

References

Sources

Fencer Intel 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.