A flaw was found in dnsmasq before version 2.83.
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.
- Published
- Jan 20, 2021
- Updated
- Jun 16, 2026
- EPSS
- 81.2% · 100th percentile
- CWE
- CWE-122
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Report tools
Action score
56
Plan
Add it to your regular patch cycle.
- CVSS
- 32 / 40 · 8.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 24 / 30 · 81.2%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| thekelleys | dnsmasq | cpe:2.3:a:thekelleys:dnsmasq |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux9.0
- fedoraproject fedora32
- fedoraproject fedora33
- thekelleys dnsmasqbefore 2.83
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
n/a dnsmasq
- dnsmasq 2.83affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | dnsmasq | before 2.83-r0 | 2.83-r0 |
| Debian:10 | dnsmasq | before 2.80-1+deb10u1 | 2.80-1+deb10u1 |
| Debian:12 | dnsmasq | before 2.83-1 | 2.83-1 |
| Debian:9 | dnsmasq | before 2.76-5+deb9u3 | 2.76-5+deb9u3 |
| openSUSE:Leap 15.1 | dnsmasq | before 2.78-lp151.5.6.1 | 2.78-lp151.5.6.1 |
| openSUSE:Leap 15.2 | dnsmasq | before 2.78-lp152.7.3.1 | 2.78-lp152.7.3.1 |
| openSUSE:Tumbleweed | dnsmasq | before 2.86-1.1 | 2.86-1.1 |
| Red Hat:enterprise_linux:8::appstream | dnsmasq | before 0:2.79-13.el8_3.1 | 0:2.79-13.el8_3.1 |
| Red Hat:enterprise_linux:8::appstream | dnsmasq-debuginfo | before 0:2.79-13.el8_3.1 | 0:2.79-13.el8_3.1 |
| Red Hat:enterprise_linux:8::appstream | dnsmasq-debugsource | before 0:2.79-13.el8_3.1 | 0:2.79-13.el8_3.1 |
| Red Hat:enterprise_linux:8::appstream | dnsmasq-utils | before 0:2.79-13.el8_3.1 | 0:2.79-13.el8_3.1 |
| Red Hat:enterprise_linux:8::appstream | dnsmasq-utils-debuginfo | before 0:2.79-13.el8_3.1 | 0:2.79-13.el8_3.1 |
| Red Hat:rhel_eus:8.1::appstream | dnsmasq | before 0:2.79-6.el8_1.1 | 0:2.79-6.el8_1.1 |
| Red Hat:rhel_eus:8.1::appstream | dnsmasq-debuginfo | before 0:2.79-6.el8_1.1 | 0:2.79-6.el8_1.1 |
| Red Hat:rhel_eus:8.1::appstream | dnsmasq-debugsource | before 0:2.79-6.el8_1.1 | 0:2.79-6.el8_1.1 |
| Red Hat:rhel_eus:8.1::appstream | dnsmasq-utils | before 0:2.79-6.el8_1.1 | 0:2.79-6.el8_1.1 |
| Red Hat:rhel_eus:8.1::appstream | dnsmasq-utils-debuginfo | before 0:2.79-6.el8_1.1 | 0:2.79-6.el8_1.1 |
| Red Hat:rhel_eus:8.2::appstream | dnsmasq | before 0:2.79-11.el8_2.2 | 0:2.79-11.el8_2.2 |
| Red Hat:rhel_eus:8.2::appstream | dnsmasq-debuginfo | before 0:2.79-11.el8_2.2 | 0:2.79-11.el8_2.2 |
| Red Hat:rhel_eus:8.2::appstream | dnsmasq-debugsource | before 0:2.79-11.el8_2.2 | 0:2.79-11.el8_2.2 |
| Red Hat:rhel_eus:8.2::appstream | dnsmasq-utils | before 0:2.79-11.el8_2.2 | 0:2.79-11.el8_2.2 |
| Red Hat:rhel_eus:8.2::appstream | dnsmasq-utils-debuginfo | before 0:2.79-11.el8_2.2 | 0:2.79-11.el8_2.2 |
| SUSE:HPE Helion OpenStack 8 | dnsmasq | before 2.78-18.15.1 | 2.78-18.15.1 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | dnsmasq | before 2.78-3.11.1 | 2.78-3.11.1 |
+3
Same product
thekelleys: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-14491Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via64This week
- CVE-2020-25682A flaw was found in dnsmasq before 2.83.53Plan
- CVE-2020-25687A flaw was found in dnsmasq before version 2.83.49Plan
- CVE-2020-25683A flaw was found in dnsmasq before version 2.83.49Plan
- CVE-2021-45957Dnsmasq 2.86 has a heap-based buffer overflow in answer_request (called from FuzzAnswerTheRequest and fuzz_rfc1035.c).40Plan
- CVE-2021-45956Dnsmasq 2.86 has a heap-based buffer overflow in print_mac (called from log_packet and dhcp_reply).40Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Alpine:dnsmasq | 2.83-r0 · Alpine:v3.10 | Package registry (OSV) |
| Debian:dnsmasq | 2.83-1 · Debian:12 | Package registry (OSV) |
| openSUSE:dnsmasq | 2.78-lp152.7.3.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| Red Hat:dnsmasq | 0:2.79-13.el8_3.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| Red Hat:dnsmasq-debuginfo | 0:2.79-13.el8_3.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| Red Hat:dnsmasq-debugsource | 0:2.79-13.el8_3.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| Red Hat:dnsmasq-utils | 0:2.79-13.el8_3.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| Red Hat:dnsmasq-utils-debuginfo | 0:2.79-13.el8_3.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| SUSE:dnsmasq | 2.78-3.11.1 · SUSE:Linux Enterprise High Performance Computing 15-ESPOS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-122 · Heap-based Buffer OverflowCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.redhat.com/show_bug.cgi?id=1881875
- lists.debian.org/debian-lts-announce/2021/03/msg00027.html
- 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
- www.debian.org/security/2021/dsa-4844
- www.jsof-tech.com/disclosures/dnspooq/
- www.kb.cert.org/vuls/id/434904
Vendor advisories and official records. Exploit/PoC links are deliberately left out.