CVE-2020-25686
Published: 19 January 2021
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.
Medium
CVSS 3 base score: 3.7
Status
| Package | Release | Status |
|---|---|---|
|
dnsmasq Launchpad, Ubuntu, Debian |
Upstream |
Released
(2.83)
|
| Ubuntu 21.10 (Impish Indri) |
Released
(2.82-1ubuntu2)
|
|
| Ubuntu 21.04 (Hirsute Hippo) |
Released
(2.82-1ubuntu2)
|
|
| Ubuntu 20.04 LTS (Focal Fossa) |
Released
(2.80-1.1ubuntu1.2)
|
|
| Ubuntu 18.04 LTS (Bionic Beaver) |
Released
(2.79-1ubuntu0.2)
|
|
| Ubuntu 16.04 ESM (Xenial Xerus) |
Released
(2.75-1ubuntu0.16.04.7)
|
|
| Ubuntu 14.04 ESM (Trusty Tahr) |
Needs triage
|