CVE-2020-25686
- State
- Published
- Severity
- Not scored
- Published
- Jan 20, 2021
- Updated
- Nov 4, 2025
- Reserved
- Sep 16, 2020
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.
Scores
The record has no CVSS score.
Weaknesses
Affected Products
| Product | Versions |
|---|---|
dnsmasqn/a |
|
References
- https://www.jsof-tech.com/disclosures/dnspooq/
- https://bugzilla.redhat.com/show_bug.cgi?id=1890125
- FEDORA-2021-84440e87bavendor-advisory
- GLSA-202101-17vendor-advisory
- DSA-4844vendor-advisory
- FEDORA-2021-2e4c3d5a9dvendor-advisory
- https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
- https://www.kb.cert.org/vuls/id/434904
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