LOW 3.7 Microsoft

CVE-2020-25684

A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However it does not use the address/port to retrieve the exact forwarded query substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452 which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

Microsoft Security Update 2021-Jan: A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However it does not use the address/port to retrieve the exact forwarded query substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452 which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

Affected Products

cm1 dnsmasq 2.85-1 on CBL Mariner 1.0

References

Published: 2021-01-12 · Source: Microsoft · Feed updated: 2026-09-07

This low severity vulnerability with a CVSS score of 3.7 was published on 2021-01-12 via Microsoft. Affected: cm1 dnsmasq 2.85-1 on CBL Mariner 1.0.

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