Vulnerability Database

300,445

Total vulnerabilities in the database

CVE-2020-25686

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.

  • Published: Jan 20, 2021
  • Updated: Nov 5, 2025
  • CVE: CVE-2020-25686
  • Severity: Low
  • Exploit:

CVSS v3:

  • Severity: Low
  • Score: 3.7
  • AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v2:

  • Severity: Low
  • Score: 4.3
  • AV:N/AC:M/Au:N/C:N/I:P/A:N

CWEs:

Software From Fixed in
thekelleys / dnsmasq - 2.83
fedoraproject / fedora 32 32.x
fedoraproject / fedora 33 33.x
debian / debian_linux 10.0 10.0.x
arista / eos 4.21 4.21.14m
arista / eos 4.22 4.22.9m
arista / eos 4.23 4.23.7m
arista / eos 4.24 4.24.5m
arista / eos 4.25 4.25.2f