CVE-2020-25684

Dnsmasq vulnerability

CVSS

3.7

EPSS

4.0%

EPSS pct

90th

Exploited

No known

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.

Affected vendor

Thekelleys

Affected product

Dnsmasq

CVSS vector

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

Weakness type (CWE)

CWE-358

Published

2021-01-20

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, high attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to low impact to integrity.

Its EPSS score of 4.0% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 90% of all scored CVEs.

Check your external exposure to CVE-2020-25684

Confirm whether Thekelleys Dnsmasq is running on any internet-facing host or subdomain.
Match discovered service fingerprints against the version affected by CVE-2020-25684.
Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2020-25684

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