HOMEVULNERABILITIESCVE-2020-25686
LOW

CVE-2020-25686

CWE-358Published: January 20, 2021· Updated: Jun 17, 2026

3.7
CVSS v3.1

Official Description

A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.

NVD Source

Technical Analysis

CVE-2020-25686 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected Vendors & Products

arista1 product(s)
eos
Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
thekelleys1 product(s)
dnsmasq
Source: NVD CPE · 5 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1890125
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=1890125
ADVISORYhttps://security.gentoo.org/glsa/202101-17
ADVISORYhttps://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
ADVISORYhttps://www.debian.org/security/2021/dsa-4844
ADVISORYhttps://www.jsof-tech.com/disclosures/dnspooq/
ADVISORYhttps://security.gentoo.org/glsa/202101-17
ADVISORYhttps://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
ADVISORYhttps://www.debian.org/security/2021/dsa-4844
ADVISORYhttps://www.jsof-tech.com/disclosures/dnspooq/

All References (15)

→
https://bugzilla.redhat.com/show_bug.cgi?id=1890125Issue Tracking · Patch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
→
https://security.gentoo.org/glsa/202101-17Third Party Advisory
→
https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4844Third Party Advisory
→
https://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=1890125Issue Tracking · Patch · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
→
https://security.gentoo.org/glsa/202101-17Third Party Advisory
→
https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61Third Party Advisory
→
https://www.debian.org/security/2021/dsa-4844Third Party Advisory
→
https://www.jsof-tech.com/disclosures/dnspooq/Third Party Advisory
→
https://www.kb.cert.org/vuls/id/434904

Quick Facts

CVE IDCVE-2020-25686
CVSS Score3.7 / 10
SeverityLOW
WeaknessCWE-358
CISA KEVNo
Affected4 vendor(s)
PublishedJan 20, 2021

Related CVEs (CWE-358)

CVE-2018-0268
10.0
CVE-2019-6742
9.8
CVE-2025-62583
9.8
CVE-2016-10229
9.8
CVE-2023-3266
9.8
CVE-2026-48797
9.3

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-25686 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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