CVE-2021-1492 | Duo Authentication Proxy Installer Denial of Service Vulnerability

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 update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-1492 is rated Low Risk (30.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-1492

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-19 0.04% 0.05% +0.01%
2 2023-03-07 0.89% 0.04% -0.84%
3 2022-04-01 — 0.89% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1492

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.6 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.3 5.2 [email protected]
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.2 [email protected]
3.6 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 4.9 [email protected]

Weakness enumeration for CVE-2021-1492

Affected software / configurations for CVE-2021-1492

Vendor Product Version Raw CPE
duo authentication_proxy < 5.2.1 cpe:2.3:a:duo:authentication_proxy:*:*:*:*:*:*:*:*

References for CVE-2021-1492

URL Tags
https://help.duo.com/s/article/6789 Vendor Advisory
cvelogic Threat Intelligence