Heap-based Buffer Overflow Affecting dnsmasq package, versions <2.82-1ubuntu2


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
19.27% (97th percentile)

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  • Snyk IDSNYK-UBUNTU2204-DNSMASQ-2777679
  • published19 Jan 2021
  • disclosed20 Jan 2021

Introduced: 19 Jan 2021

CVE-2020-25682  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade Ubuntu:22.04 dnsmasq to version 2.82-1ubuntu2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream dnsmasq package and not the dnsmasq package as distributed by Ubuntu. See How to fix? for Ubuntu:22.04 relevant fixed versions and status.

A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

CVSS Scores

version 3.1