CVE-2021-1492

Q: How do I fix CVE-2021-1492?

Upgrade authentication proxy to 5.2.1 or later.

Q: Is CVE-2021-1492 being actively exploited?

Not that we know of. CVE-2021-1492 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.

Q: How severe is CVE-2021-1492?

CVE-2021-1492 has a CVSS v3 base score of 6.6, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2021-1492 affect?

Published advisories record a fix for authentication proxy (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

MEDIUM

6.6

CVSS v3

NVD

Description

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.

CWE-64

How to fix

Remediation Available

authentication proxyNVD

Affected:< 5.2.1Fixed in:5.2.1CVE-2021-1492derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H

Exploit Intelligence

0.27%probability of exploitation in 30 days

19thpercentile

Low risk: more likely to be exploited than 19% of all known CVEs.

References

Vendor Advisory1

help.duo.com

Related Vulnerabilities

Other CWE-64 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-52521	High	7.8	0.3%	-	-
CVE-2021-41562	Medium	6.1	0.2%	-	Fix
CVE-2025-53503	High	7.8	0.2%	-	Fix
CVE-2025-7376	Medium	5.9	0.2%	-	-
CVE-2025-48443	Medium	6.7	0.2%	-	Fix
CVE-2025-52837	High	7.8	0.2%	-	Fix

Common questions

How do I fix CVE-2021-1492?

Upgrade authentication proxy to 5.2.1 or later.

Is CVE-2021-1492 being actively exploited?

Not that we know of. CVE-2021-1492 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.

How severe is CVE-2021-1492?

CVE-2021-1492 has a CVSS v3 base score of 6.6, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-1492 affect?

Published advisories record a fix for authentication proxy (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.