dnsmasq: A flaw was found in dnsmasq before version 2.83
CVE-2020-25685 is fixed in 4 products on 1 platform, first by dnsmasq 2.79-1ubuntu0.2, released January 18, 2021. It is not reported as exploited. Patch Radar priority: Routine.
A flaw was found in dnsmasq before version 2.83. When getting a reply froma forwarded query, dnsmasq checks in forward.c:reply_query(), which is theforwarded query that matches the reply, by only using a weak hash of thequery name. Due to the weak hash (CRC32 when dnsmasq is compiled withoutDNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to findseveral different domains all having the same hash, substantially reducingthe number of attempts they would have to perform to forge a reply and getit accepted by dnsmasq. This is in contrast with RFC5452, which specifiesthat the query name is one of the attributes of a query that must be usedto match a reply. This flaw could be abused to perform a DNS CachePoisoning attack. If chained with CVE-2020-25684 the attack complexity of asuccessful attack is reduced. The highest threat from this vulnerability isto data integrity.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| dnsmasq · RHEL 8 | 0:2.79-13.el8_3.1 | RHSA-2021:0150 | Jan 19, 2021 |
| dnsmasq · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.2 | dnsmasq 2.79-1ubuntu0.2 | Jan 18, 2021 |
| dnsmasq · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.2 | dnsmasq 2.80-1.1ubuntu1.2 | Jan 18, 2021 |
| dnsmasq · Ubuntu 24.10 (oracular) | 2.82-1ubuntu2 | dnsmasq 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq · Ubuntu 25.04 (plucky) | 2.82-1ubuntu2 | dnsmasq 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq · ol 8 | 0:2.79-13.el8_3.1 | ELSA-2021-0150 | Jan 20, 2021 |
| dnsmasq-base · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.2 | dnsmasq-base 2.79-1ubuntu0.2 | Jan 18, 2021 |
| dnsmasq-base · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.2 | dnsmasq-base 2.80-1.1ubuntu1.2 | Jan 18, 2021 |
| dnsmasq-base · Ubuntu 24.10 (oracular) | 2.82-1ubuntu2 | dnsmasq-base 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-base · Ubuntu 25.04 (plucky) | 2.82-1ubuntu2 | dnsmasq-base 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-base-lua · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.2 | dnsmasq-base-lua 2.79-1ubuntu0.2 | Jan 18, 2021 |
| dnsmasq-base-lua · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.2 | dnsmasq-base-lua 2.80-1.1ubuntu1.2 | Jan 18, 2021 |
| dnsmasq-base-lua · Ubuntu 24.10 (oracular) | 2.82-1ubuntu2 | dnsmasq-base-lua 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-base-lua · Ubuntu 25.04 (plucky) | 2.82-1ubuntu2 | dnsmasq-base-lua 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-utils · RHEL 8 | 0:2.79-13.el8_3.1 | RHSA-2021:0150 | Jan 19, 2021 |
| dnsmasq-utils · Ubuntu 18.04.6 LTS (bionic) | 2.79-1ubuntu0.2 | dnsmasq-utils 2.79-1ubuntu0.2 | Jan 18, 2021 |
| dnsmasq-utils · Ubuntu 20.04 LTS (focal) | 2.80-1.1ubuntu1.2 | dnsmasq-utils 2.80-1.1ubuntu1.2 | Jan 18, 2021 |
| dnsmasq-utils · Ubuntu 24.10 (oracular) | 2.82-1ubuntu2 | dnsmasq-utils 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-utils · Ubuntu 25.04 (plucky) | 2.82-1ubuntu2 | dnsmasq-utils 2.82-1ubuntu2 | Jan 19, 2021 |
| dnsmasq-utils · ol 8 | 0:2.79-13.el8_3.1 | ELSA-2021-0150 | Jan 20, 2021 |
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