CVE-2020-25687

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.

How to fix CVE-2020-25687

To remediate CVE-2020-25687, upgrade the affected package to a fixed version below.

• —upgrade to 2.83-r0 or later
• —upgrade to 2.83-1 or later

Is CVE-2020-25687 being exploited?

Moderate — EPSS is 22.0%. Track this CVE but it's not at the top of the prioritisation list.

Affected packages (2)

• from 0, < 2.83-r0
• from 0, < 2.83-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2020-25687
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2020-25687