A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
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Tue, 04 Nov 2025 20:30:00 +0000
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Status: PUBLISHED
Assigner: redhat
Published: 2021-01-20T16:47:17.000Z
Updated: 2025-11-04T19:12:14.331Z
Reserved: 2020-09-16T00:00:00.000Z
Link: CVE-2020-25686
No data.
Status : Modified
Published: 2021-01-20T17:15:13.000
Modified: 2025-11-04T20:15:57.490
Link: CVE-2020-25686