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Vulnerability · Published Jan 20, 2021 · Assigned by redhat

CVE-2020-25687

Medium 5.9

In plain English

A medium-severity heap buffer overflow in dnsmasq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 89.3% (higher than 99.8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.9Medium
Exploit odds (30 days)89.3%top 0.2% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20dnsmasq2.83-r0ALPINE-CVE-2020-25687
Alpine:v3.21dnsmasq2.83-r0ALPINE-CVE-2020-25687
Alpine:v3.22dnsmasq2.83-r0ALPINE-CVE-2020-25687
Alpine:v3.23dnsmasq2.83-r0ALPINE-CVE-2020-25687
Alpine:v3.24dnsmasq2.83-r0ALPINE-CVE-2020-25687
Debian:12dnsmasq2.83-1DEBIAN-CVE-2020-25687
Debian:13dnsmasq2.83-1DEBIAN-CVE-2020-25687
Debian:14dnsmasq2.83-1DEBIAN-CVE-2020-25687

Affected products (as reported)

VendorProductVersions
n/a dnsmasq dnsmasq 2.83

Weakness: CWE-122

References