PT-2021-7236 · Dnsmasq+9 · Dnsmasq+9
Published
2021-04-08
·
Updated
2025-12-03
·
CVE-2021-3448
CVSS v2.0
4.3
Medium
| Vector | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Name of the Vulnerable Software and Affected Versions
dnsmasq versions prior to 2.85
Description
The issue is related to a flaw in the security check implementation for standard elements in the DNS server. This flaw can be exploited by a remote attacker to perform a DNS cache poisoning attack, which can compromise data integrity. An attacker on the network can forge a reply and get it accepted by dnsmasq by guessing the random transmission ID, as dnsmasq uses a fixed port while forwarding queries when configured to use a specific server for a given network interface.
Recommendations
For versions prior to 2.85, update to version 2.85 or later to resolve the issue. As a temporary workaround, consider restricting access to the vulnerable DNS server to minimize the risk of exploitation. Avoid using the fixed port for forwarding queries until the issue is resolved.
Exploit
Fix
Improperly Implemented Security Check for Standard
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Weakness Enumeration
Related Identifiers
Affected Products
Alt Linux
Almalinux
Astra Linux
Centos
Linuxmint
Red Hat
Rocky Linux
Suse
Ubuntu
Dnsmasq