CVE-2020-25683

MEDIUM EPSS 99.7%
Published Jan 20, 20215y ago · Modified Jun 17, 20262w ago
5.9 CVSS 3.1
Medium
Find Similar
Published Jan 20, 2021 5y ago
Last Modified Jun 17, 2026 2w ago

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. A remote attacker, who can create valid DNS replies, could use this flaw 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 get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

CVSS Details

Base Score
5.9
Exploitability
2.2
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
99.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-122

Affected Products 5

VendorProductVersionRange
thekelleysdnsmasq* <2.83
fedoraprojectfedora32any
fedoraprojectfedora33any
debiandebian_linux9.0any
debiandebian_linux10.0any

References 8

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=1882018
    Issue TrackingPatchThird Party Advisory
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
    Mailing ListThird Party Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
  • security.gentoo.org https://security.gentoo.org/glsa/202101-17
    Third Party Advisory
  • debian.org https://www.debian.org/security/2021/dsa-4844
    Third Party Advisory
  • jsof-tech.com https://www.jsof-tech.com/disclosures/dnspooq/
    Third Party Advisory
  • kb.cert.org https://www.kb.cert.org/vuls/id/434904

Remediation

  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=1882018
    Issue TrackingPatchThird Party Advisory