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Improperly Implemented Security Check for Standard


Severity Low
Score 3.7/10


A flaw was found in dnsmasq prior to 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.

  • HIGH
  • LOW
  • NONE
  • NONE
  • NONE
  • NONE

CWE-358 - Improperly Implemented Security Check for Standard

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

Advisory Timeline

  • Published