How severe is CVE-2020-3427?

CVE-2020-3427 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-3427 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3427?

CVE-2020-3427 affects Cisco Duo Authentication For Windows Logon And Rdp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3427?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-3427 published?

CVE-2020-3427 was published on 2020-10-14 and last updated on 2026-06-17.

CVE-2020-3427

CVE-2020-3427 is a medium-severity vulnerability in Cisco Duo Authentication For Windows Logon And Rdp with a CVSS 3.x base score of 6.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-280.

Key facts

Severity: Medium (CVSS 3.x base score 6.6)
CVSS v2: 4.6
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-280
Affected product: Cisco Duo Authentication For Windows Logon And Rdp
Published: 2020-10-14
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-3427?: 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.
How severe is CVE-2020-3427?: CVE-2020-3427 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-3427 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3427?: CVE-2020-3427 affects Cisco Duo Authentication For Windows Logon And Rdp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3427?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3427 published?: CVE-2020-3427 was published on 2020-10-14 and last updated on 2026-06-17.

References

https://duo.com/docs/rdp-notes

Affected products (1)

cpe:2.3:a:cisco:duo_authentication_for_windows_logon_and_rdp:*:*:*:*:*:*:*:*

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