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CVE-2020-25682

58
FAUCET Score

CVE-2020-25682 is a critical buffer overflow vulnerability in dnsmasq versions prior to 2.83, affecting various Debian and Fedora distributions. This flaw allows an unauthenticated attacker on the network to craft malicious DNS replies, leading to arbitrary code execution, data confidentiality and integrity breaches, and system unavailability. With a CVSS score of 8.1 (HIGH), the attack requires high complexity but no user interaction. While there are no known public exploits or Metasploit modules, the vulnerability has garnered significant community discussion and media coverage, indicating high awareness despite its inactive status on the CISA KEV catalog.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.83CPE matchmatch criteria
cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.1HIGH

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
70.75%
Probability of exploitation in next 30 days
EPSS Percentile
99.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.7075 is in the 99th percentile among its peer group of 8,920 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

microsoftpatch availablevia msrc
Product: 19065-16820Fixed in: 2.85-1
microsoftpatch availablevia msrc
Product: cm1 dnsmasq 2.85-1 on CBL Mariner 1.0Fixed in: 2.85-1
redhatpatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: dnsmasq-0:2.79-13.el8_3.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.1 Extended Update SupportFixed in: dnsmasq-0:2.79-6.el8_1.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.2 Extended Update SupportFixed in: dnsmasq-0:2.79-11.el8_2.2
View patch

Vendor Advisories (2)

redhatCVE-2020-25682Important

dnsmasq: buffer overflow in extract_name() due to missing length check when DNSSEC is enabled

Jan 19, 2021
microsoft2021-Jan/CVE-2020-25682Important

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.

Jan 12, 2021

References

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