A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-2604-1 | dnsmasq security update |
Debian DSA |
DSA-4844-1 | dnsmasq security update |
EUVD |
EUVD-2020-18346 | A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity. |
Ubuntu USN |
USN-4698-1 | Dnsmasq vulnerabilities |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 04 Nov 2025 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Status: PUBLISHED
Assigner: redhat
Published:
Updated: 2025-11-04T19:12:12.109Z
Reserved: 2020-09-16T00:00:00.000Z
Link: CVE-2020-25684
No data.
Status : Modified
Published: 2021-01-20T16:15:14.163
Modified: 2025-11-04T20:15:57.223
Link: CVE-2020-25684
OpenCVE Enrichment
No data.
Debian DLA
Debian DSA
EUVD
Ubuntu USN