DEBIAN-CVE-2020-25686
Record from OSV · Published January 20, 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.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| dnsmasq | Debian:13 | 2.83-1 |
| dnsmasq | Debian:14 | 2.83-1 |
| dnsmasq | Debian:12 | 2.83-1 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Debian:13 | dnsmasq | 0 |
| Debian:14 | dnsmasq | 0 |
| Debian:12 | dnsmasq | 0 |
Timeline
- Jan 20, 2021 CVE Published
- Oct 26, 2026 CVE Updated
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