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Vulnerability · Published Jan 20, 2021 · Assigned by redhat

CVE-2020-25684

Low 3.7

In plain English

A low-severity security flaw in dnsmasq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 4.2% (higher than 91% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)3.7Low
Exploit odds (30 days)4.2%top 9.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling1Public PoC

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20dnsmasq2.83-r0ALPINE-CVE-2020-25684
Alpine:v3.21dnsmasq2.83-r0ALPINE-CVE-2020-25684
Alpine:v3.22dnsmasq2.83-r0ALPINE-CVE-2020-25684
Alpine:v3.23dnsmasq2.83-r0ALPINE-CVE-2020-25684
Alpine:v3.24dnsmasq2.83-r0ALPINE-CVE-2020-25684
Debian:12dnsmasq2.83-1DEBIAN-CVE-2020-25684
Debian:13dnsmasq2.83-1DEBIAN-CVE-2020-25684
Debian:14dnsmasq2.83-1DEBIAN-CVE-2020-25684

Affected products (as reported)

VendorProductVersions
n/a dnsmasq dnsmasq 2.83

Weakness: CWE-358

References