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.
CVE-2020-25682
Score elevated to 8.8 because EPSS predicts 71% probability of exploitation within the next 30 days (top 0.7% of all CVEs). NVD baseline CVSS 8.1 retained for reference. Confidence: see factors.
- High exploitation likelihood — EPSS 71%
A fix is available — apply it.
- CVSS v3
- 8.1
- EG Score
- 8.8(high)
- EG Risk
- 72(Track)EG Risk 72/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity88% × 45%Exploitation71% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 71%
- EPSS %ILE
- 99%
- KEV
- Not listed
Published
January 20, 2021
Last Modified
November 4, 2025
Advisory Details (6)
Auto-updated Sep 15, 2026[SECURITY] Fedora 32 Update: dnsmasq-2.84-1.fc32 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/[SECURITY] [DLA 2604-1] dnsmasq security update
https://lists.debian.org/debian-lts-announce/2021/03/msg00027.html1882014 – (CVE-2020-25682) CVE-2020-25682 dnsmasq: buffer overflow in extract_name() due to missing length check when DNSSEC is enabled
Affected: Red Hat Enterprise Linux 5, 6, and 7 as they are not compiled with DNSSEC support.
https://bugzilla.redhat.com/show_bug.cgi?id=1882014Dnsmasq: Multiple vulnerabilities (GLSA 202101-17) — Gentoo security
https://security.gentoo.org/glsa/202101-17[SECURITY] Fedora 33 Update: dnsmasq-2.83-1.fc33 - package-announce - Fedora mailing-lists
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/Patch Availability(4)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | dnsmasq-utils (2.80-1.1ubuntu1.2) @ focal | 2026-05-26 | ubuntu |
| 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-0:2.79-11.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.
Affected Packages
(21 across 21 ecosystems)
Alpine:v3.10(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.15(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.16(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.17(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.18(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.19(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.20(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.21(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.22(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.23(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Alpine:v3.24(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-r0 | — |
Debian:10(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | 2.80-1 | 2.80-1+deb10u1 | — |
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-1 | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-1 | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-1 | — |
Debian:14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | — | 2.83-1 | — |
Debian:9(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| dnsmasq | 2.76-5, 2.76-5+deb9u1, 2.76-5+deb9u2 | 2.76-5+deb9u3 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(5)
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-2020-256822021-01-29
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.
- Red HatRHSA-2021:0150IMPORTANT2021-01-19
RHSA-2021:0150 — Important
- Red HatRHSA-2021:0151IMPORTANT2021-01-19
RHSA-2021:0151 — Important
- Red HatRHSA-2021:0152IMPORTANT2021-01-19
RHSA-2021:0152 — Important
- UbuntuUSN-4698-1MEDIUM
Dnsmasq vulnerabilities
Data Freshness Timeline
(refreshed 6× in last 7d / 21× 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.
Showing the most recent 100 of 111 total refreshes for this CVE.
- 2026-09-18 19:23 UTCEPSS rescore
- 2026-09-17 19:22 UTCEPSS rescore
- 2026-09-17 19:22 UTCEPSS rescore
- 2026-09-16 14:04 UTCEPSS rescore
- 2026-09-15 03:06 UTCEPSS rescore
- 2026-09-15 03:06 UTCEPSS rescore
- 2026-09-12 14:56 UTCEPSS rescore
- 2026-09-11 09:32 UTCEPSS rescore
- 2026-09-10 09:29 UTCEPSS rescore
- 2026-09-08 21:56 UTCEPSS rescore
- 2026-09-06 23:31 UTCOSV refresh
- 2026-09-06 13:44 UTCEPSS rescore
- 2026-09-05 15:24 UTCEPSS rescore
- 2026-09-04 05:03 UTCEPSS rescore
- 2026-09-02 14:08 UTCEPSS rescore
- 2026-09-01 03:32 UTCEPSS rescore
- 2026-08-30 19:14 UTCEPSS rescore
- 2026-08-26 14:42 UTCEPSS rescore
- 2026-08-25 13:45 UTCEPSS rescore
- 2026-08-21 23:45 UTCEPSS rescore
- 2026-08-20 22:52 UTCEPSS rescore
- 2026-08-20 09:31 UTCOSV refresh
- 2026-08-19 17:00 UTCEPSS rescore
- 2026-08-18 13:44 UTCEPSS rescore
- 2026-08-16 02:11 UTCEPSS rescore
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- 2026-08-15 01:26 UTCEPSS rescore
- 2026-08-12 13:47 UTCEPSS rescore
- 2026-08-07 16:23 UTCEPSS rescore
- 2026-08-05 19:14 UTCEPSS rescore
- 2026-08-05 05:10 UTCOSV refresh
- 2026-08-04 15:06 UTCEPSS rescore
- 2026-08-04 10:34 UTCEPSS rescore
- 2026-08-03 10:32 UTCEPSS rescore
- 2026-07-30 16:25 UTCEPSS rescore
- 2026-07-28 15:32 UTCEPSS rescore
- 2026-07-25 14:15 UTCEPSS rescore
- 2026-07-25 14:14 UTCEPSS rescore
- 2026-07-24 14:14 UTCEPSS rescore
- 2026-07-23 01:51 UTCEG score recompute▲ 0.70
- 2026-07-22 22:37 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-19 03:22 UTCOSV refresh
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 01:57 UTCEPSS rescore
- 2026-07-12 05:44 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-11 08:25 UTCEPSS rescore
- 2026-07-09 19:07 UTCEPSS rescore
- 2026-07-07 13:43 UTCEPSS rescore
- 2026-07-07 13:43 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 09:48 UTCOSV refresh
- 2026-06-28 14:05 UTCEPSS rescore
- 2026-06-28 04:54 UTCEPSS rescore
- 2026-06-28 04:54 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
- 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
- 2026-06-15 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 15:43 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
- 2026-06-07 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
- 2026-05-31 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
Frequently asked(5)
What is CVE-2020-25682?
When was CVE-2020-25682 disclosed?
Is CVE-2020-25682 actively exploited?
What is the CVSS score of CVE-2020-25682?
How do I remediate CVE-2020-25682?
Dependency Blast Radius
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