What is CVE-2021-1492?

CVE-2021-1492 is a medium-severity vulnerability in Cisco Duo Authentication Proxy, classified under CWE-64. CVSS score: 6.6/10. Published 2021-03-25.

How severe is CVE-2021-1492?

Medium severity. CVSS v3 base score is 6.6 out of 10.

Vulnerability in Cisco Duo Authentication Proxy

CVE-2021-1492

The Duo Authentication Proxy installer prior to 5.2.1 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 Duo Authentication Proxy installer, cause Denial of Service (DoS) by deleting file(s), or replace system files to potentially achieve elevation of privileges. This is only exploitable during new installations, while the installer is running, and is not exploitable once installation has finished. Versions 5.2.1 of Duo Authentication Proxy installer addresses this issue.

Published 2021-03-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.6 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (17.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 17.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Cisco Duo Authentication Proxy — versions unspecified
Duo Authentication Proxy
Microsoft Windows

Weakness classification (CWE)

CWE-64

References

help.duo.com/s/article/6789 (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2021-1492?: CVE-2021-1492 is a medium-severity vulnerability in Cisco Duo Authentication Proxy, classified under CWE-64. CVSS score: 6.6/10. Published 2021-03-25.
How severe is CVE-2021-1492?: Medium severity. CVSS v3 base score is 6.6 out of 10.