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No exploitation reportedFix available

CVE-2020-25681

No exploitation reported by the sources we read.

  • Published2021-01-20
  • WeaknessCWE-122

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Timeline

dates in UTC
  1. 2021-01-2017:15CVE publishedNVD
  2. 2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-25681?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-25681?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Debian debian linux
BranchAffectedFixed in
9.0= 9.0no fix published
10.0= 10.0no fix published
Fedoraproject fedora
BranchAffectedFixed in
32.x= 32no fix published
33.x= 33no fix published
Thekelleys dnsmasq
BranchAffectedFixed in
2.83< 2.832.83

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.18.1read 2026-10-23
  • NVDCVSS 2.08.3read 2026-10-23
  • CNAweakness (CWE)CWE-122read 2026-10-23
  • FIRST EPSSEPSS score84.1 %read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-01-20
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-25681?

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Is CVE-2020-25681 actively exploited?

Active exploitation of CVE-2020-25681 has not been confirmed. Its EPSS score was 84.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-25681?

CVE-2020-25681 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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