A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
CVE-2020-25684
Score 3.7 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 3.7; sources differ by 0.0.
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 3.7
- EG Score
- 3.7(medium)
- EPSS
- 89.4%
- KEV
- Not listed
Published
January 20, 2021
Last Modified
November 4, 2025
References (17)
- secalert@redhathttps://bugzilla.redhat.com/show_bug.cgi?id=1889686
- secalert@redhathttps://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
- secalert@redhathttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
- secalert@redhathttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- secalert@redhathttps://security.gentoo.org/glsa/202101-17
- secalert@redhathttps://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
- secalert@redhathttps://www.debian.org/security/2021/dsa-4844
- secalert@redhathttps://www.jsof-tech.com/disclosures/dnspooq/
- af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1889686
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/
- af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/
- af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202101-17
- af854a3a-2127-422b-91ae-364da2661108https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61
- af854a3a-2127-422b-91ae-364da2661108https://www.debian.org/security/2021/dsa-4844
Patch Availability(12)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | dnsmasq-utils (2.75-1ubuntu0.16.04.7) @ xenial | 2026-05-26 | ubuntu |
| redhat | redhat-virtualization-host-0:4.4.4-20210201.0.el8_3 | 2021-02-03 | redhat |
| redhat | redhat-virtualization-host-0:4.3.13-20210127.0.el7_9 | 2021-02-03 | redhat |
| redhat | dnsmasq-0:2.66-14.el7_2.3 | 2021-01-25 | redhat |
| redhat | dnsmasq-0:2.66-21.el7_3.3 | 2021-01-25 | redhat |
| redhat | dnsmasq-0:2.76-7.el7_6.2 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.76-10.el7_7.2 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.79-13.el8_3.1 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.79-6.el8_1.1 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.76-16.el7_9.1 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.76-2.el7_4.3 | 2021-01-19 | redhat |
| redhat | dnsmasq-0:2.79-11.el8_2.2 | 2021-01-19 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(13)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2020-256842021-01-29
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However it does not use the address/port to retrieve the exact forwarded query substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452 which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
- Red HatRHSA-2021:0150MODERATE2021-01-19
RHSA-2021:0150 — Moderate
- Red HatRHSA-2021:0151MODERATE2021-01-19
RHSA-2021:0151 — Moderate
- Red HatRHSA-2021:0152MODERATE2021-01-19
RHSA-2021:0152 — Moderate
- Red HatRHSA-2021:0153MODERATE2021-01-19
RHSA-2021:0153 — Moderate
- Red HatRHSA-2021:0154MODERATE2021-01-19
RHSA-2021:0154 — Moderate
- Red HatRHSA-2021:0155MODERATE2021-01-19
RHSA-2021:0155 — Moderate
- Red HatRHSA-2021:0156MODERATE2021-01-19
RHSA-2021:0156 — Moderate
- Red HatRHSA-2021:0240MODERATE2021-01-19
RHSA-2021:0240 — Moderate
- Red HatRHSA-2021:0245MODERATE2021-01-19
RHSA-2021:0245 — Moderate
- Red HatRHSA-2021:0395MODERATE2021-01-19
RHSA-2021:0395 — Moderate
- Red HatRHSA-2021:0401MODERATE2021-01-19
RHSA-2021:0401 — Moderate
- UbuntuUSN-4698-1MEDIUM
Dnsmasq vulnerabilities
Data Freshness Timeline
(refreshed 9× in last 7d / 42× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-08 15:12 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 16:25 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-06 02:21 UTCEPSS rescore
- 2026-07-05 02:27 UTCEPSS rescore
- 2026-07-04 06:29 UTCEPSS rescore
- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-07-01 10:18 UTCOSV refresh
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-29 14:04 UTCEPSS rescore
- 2026-06-28 14:05 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-25 13:47 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-24 14:03 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
- 2026-06-23 21:31 UTCEPSS rescore
Show 53 moreShow fewer
- 2026-06-22 14:23 UTCEPSS rescore
- 2026-06-22 14:23 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 01:57 UTCEPSS rescore
- 2026-06-21 01:57 UTCEPSS rescore
- 2026-06-19 19:23 UTCEPSS rescore
- 2026-06-18 17:50 UTCEPSS rescore
- 2026-06-17 17:50 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-15 17:46 UTCEPSS rescore
- 2026-06-14 23:15 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 22:58 UTCEPSS rescore
- 2026-06-13 16:13 UTCOSV refresh
- 2026-06-12 23:10 UTCEPSS rescore
- 2026-06-11 13:58 UTCEPSS rescore
- 2026-06-10 22:16 UTCEPSS rescore
- 2026-06-10 22:16 UTCEPSS rescore
- 2026-06-10 13:20 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-08 14:15 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-06 13:45 UTCEPSS rescore
- 2026-06-06 13:45 UTCEPSS rescore
- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 22:45 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-05 06:08 UTCEPSS rescore
- 2026-06-04 13:10 UTCEPSS rescore
- 2026-06-04 13:10 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-02 20:11 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-06-01 13:50 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 22:29 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-31 00:15 UTCEPSS rescore
- 2026-05-29 13:42 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-28 13:43 UTCEPSS rescore
- 2026-05-27 13:39 UTCEPSS rescore
- 2026-05-26 21:51 UTCEG score recompute
- 2026-05-26 21:51 UTCVendor advisory
- 2026-05-26 21:51 UTCGHSA enrichment
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-24 16:48 UTCEPSS rescore
Frequently asked(5)
What is CVE-2020-25684?
When was CVE-2020-25684 disclosed?
Is CVE-2020-25684 actively exploited?
What is the CVSS score of CVE-2020-25684?
How do I remediate CVE-2020-25684?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2020-25684
Is Your Infrastructure Affected by CVE-2020-25684?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.