Is CVE-2021-3448 in the CISA KEV catalog?

No. CVE-2021-3448 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-3448?

CVE-2021-3448 has a CVSS v3 base score of 4.0 (MEDIUM).

What is the EPSS score for CVE-2021-3448?

CVE-2021-3448 has an EPSS score of 1.99% (78th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-3448?

Upgrade dnsmasq on debian 11 to 2.85-1 or later. Fixes are available for 4 affected products.

CVE & CISA-KEV Catalog

CVE-2021-3448

MEDIUMEPSS 78th pctl

4.0

CVSS v3

NVD

Description

A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.

CWE-358

How to fix

Remediation Available

dnsmasqDebian

Fixed in:2.85-1CVE-2021-3448

dnsmasqUbuntu

Fixed in:2.79-1ubuntu0.16.04.1+esm1USN-4976-2

Fixed in:2.79-1ubuntu0.4USN-4976-1

Fixed in:2.80-1.1ubuntu1.4USN-4976-1

dnsmasq-baseUbuntu

Fixed in:2.79-1ubuntu0.16.04.1+esm1USN-4976-2

Fixed in:2.79-1ubuntu0.4USN-4976-1

Fixed in:2.80-1.1ubuntu1.4USN-4976-1

dnsmasq-utilsUbuntu

Fixed in:2.79-1ubuntu0.16.04.1+esm1USN-4976-2

Fixed in:2.79-1ubuntu0.4USN-4976-1

Fixed in:2.80-1.1ubuntu1.4USN-4976-1

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 VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

1.99%probability of exploitation in 30 days

78thpercentile

Elevated risk: more likely to be exploited than 78% of all known CVEs.

References

Patch2

Third-Party Advisory1

security.gentoo.org

Other references3

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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 2025-12-03.