CVE-2020-25686
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-25686
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-25686.html
Vendor advisory: arch — https://security.archlinux.org/ASA-202101-38
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| arch | fixed | 2.83-1 | |
| debian | bookworm | fixed | 2.83-1 |
| sles | affected | | |
| debian | bullseye | fixed | 2.83-1 |
| debian | forky | fixed | 2.83-1 |
| debian | sid | fixed | 2.83-1 |
| debian | trixie | fixed | 2.83-1 |
References
Verify integrity in audit chain (admin only). AS-IS.