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.
https://www.jsof-tech.com/disclosures/dnspooq/
https://bugzilla.redhat.com/show_bug.cgi?id=1890125
https://security.gentoo.org/glsa/202101-17
https://www.debian.org/security/2021/dsa-4844
https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
Source: MITRE
Published: 2021-01-20
Updated: 2022-02-14
Type: CWE-358
Base Score: 4.3
Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 8.6
Severity: MEDIUM
Base Score: 3.7
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Impact Score: 1.4
Exploitability Score: 2.2
Severity: LOW