Vulnerabilities
Misconfiguration
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CVE Vulnerabilities

CVE-2021-3448

Improperly Implemented Security Check for Standard

Published: Apr 08, 2021 | Modified: Dec 03, 2025
CVSS 3.x
4
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
CVSS 2.x
4.3 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N
RedHat/V2
RedHat/V3
4 MODERATE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Ubuntu
LOW
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Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2021-3448
CWEhttps://cwe.mitre.org/data/definitions/358.html

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.

Weakness

The product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique.

Affected Software

NameVendorStart VersionEnd Version
DnsmasqThekelleys*2.85 (excluding)
Red Hat Enterprise Linux 8RedHatdnsmasq-0:2.79-19.el8*
DnsmasqUbuntubionic*
DnsmasqUbuntudevel*
DnsmasqUbuntuesm-infra-legacy/trusty*
DnsmasqUbuntuesm-infra/bionic*
DnsmasqUbuntuesm-infra/focal*
DnsmasqUbuntuesm-infra/xenial*
DnsmasqUbuntufocal*
DnsmasqUbuntugroovy*
DnsmasqUbuntuhirsute*
DnsmasqUbuntuimpish*
DnsmasqUbuntujammy*
DnsmasqUbuntukinetic*
DnsmasqUbuntulunar*
DnsmasqUbuntumantic*
DnsmasqUbuntunoble*
DnsmasqUbuntuoracular*
DnsmasqUbuntuplucky*
DnsmasqUbuntuprecise/esm*
DnsmasqUbuntutrusty*
DnsmasqUbuntutrusty/esm*
DnsmasqUbuntuupstream*
DnsmasqUbuntuxenial*

References

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