CVE & CISA-KEV Catalog

CVE-2020-25684

LOWEPSS 89th pctl
3.7
CVSS v3
NVD

Description

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.

CWE-358

How to fix

Remediation Available
dnsmasqDebian
Fixed in:2.83-1CVE-2020-25684
Fixed in:2.83-1CVE-2020-25684
Fixed in:2.83-1CVE-2020-25684
Fixed in:2.83-1CVE-2020-25684
dnsmasqUbuntu
Fixed in:2.75-1ubuntu0.16.04.7USN-4698-1
Fixed in:2.79-1ubuntu0.2USN-4698-1
Fixed in:2.80-1.1ubuntu1.2USN-4698-1
dnsmasq-baseUbuntu
Fixed in:2.75-1ubuntu0.16.04.7USN-4698-1
Fixed in:2.79-1ubuntu0.2USN-4698-1
Fixed in:2.80-1.1ubuntu1.2USN-4698-1
dnsmasq-utilsUbuntu
Fixed in:2.75-1ubuntu0.16.04.7USN-4698-1
Fixed in:2.79-1ubuntu0.2USN-4698-1
Fixed in:2.80-1.1ubuntu1.2USN-4698-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityLow
AvailabilityNone

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Exploit Intelligence

4.04%probability of exploitation in 30 days
89thpercentile

Elevated risk: more likely to be exploited than 89% of all known CVEs.

References

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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.