DNS Cache Poisoning attack in dnsmasq

Published: 2021-04-13
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2021-3448
Exploitation vector Network
Public exploit N/A
Vulnerable software
Server applications / DNS servers

Vendor GNU

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Insufficient verification of data authenticity

EUVDB-ID: #VU52065

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3448

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

Exploit availability: No


The vulnerability allows a remote attacker to perform a DNS Cache Poisoning attack.

The vulnerability exists due to dnsmasq relies only on transmission ID when processing DNS queries and uses the same port for outgoing requests, when configured to given network interface. A remote attacker can guess the random transmission ID to forge a reply and get it accepted by dnsmasq.As a result, an attacker can perform a DNS Cache Poisoning attack.


Install updates from vendor's website.

Vulnerable software versions

Dnsmasq: 2.0 - 2.84

CPE2.3 External links


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.