CVE-2020-25687 Information

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.

CVSS Vector

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

Reference

https://www.jsof-tech.com/disclosures/dnspooq/ https://bugzilla.redhat.com/show_bug.cgi?id=1891568 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/ https://security.gentoo.org/glsa/202101-17 https://www.debian.org/security/2021/dsa-4844 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/ https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.9