Heap-based buffer overflow in dnsmasq
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | dnsmasq | dnsmasq 2.83 | — | No fix listed | CNA |
- dnsmasq Vendor— Affected dnsmasq 2.83 Fixed in — No fix listed CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* | before 2.83 | Vulnerable | Thekelleys |
| cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | 32 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
- cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* Versions before 2.83 Vulnerable ·Thekelleys
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
Remediation
Red Hat 3 advisories
- RHSA-2021:0150 Released 2021-01-19 · Red Hat rating Importantdnsmasq security update
- Red Hat Enterprise Linux AppStream (v. 8) dnsmasq-2.79-13.el8_3.1, dnsmasq-utils-2.79-13.el8_3.1
- RHSA-2021:0151 Released 2021-01-19 · Red Hat rating Importantdnsmasq security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.2) dnsmasq-2.79-11.el8_2.2, dnsmasq-utils-2.79-11.el8_2.2
- RHSA-2021:0152 Released 2021-01-19 · Red Hat rating Importantdnsmasq security update
- Red Hat Enterprise Linux AppStream EUS (v. 8.1) dnsmasq-2.79-6.el8_1.1, dnsmasq-utils-2.79-6.el8_1.1
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
dnsmasq — FEDORA-2021-2e4c3d5a9d
7 records Highest priority Priority HIGH 4 HIGH, 3 LOW
Other records, highest priority first
- TI-2020-15698 Heap-based buffer overflow in dnsmasqPriority HIGH 74
- TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- Advisory ·
dnsmasq — FEDORA-2021-84440e87ba
7 records Highest priority Priority HIGH 4 HIGH, 3 LOW
Other records, highest priority first
- TI-2020-15698 Heap-based buffer overflow in dnsmasqPriority HIGH 74
- TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
Show 2 more groups
- Advisory ·
dnsmasq — GLSA-202101-17
7 records Highest priority Priority HIGH 4 HIGH, 3 LOW
Other records, highest priority first
- TI-2020-15698 Heap-based buffer overflow in dnsmasqPriority HIGH 74
- TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- Advisory ·
dnsmasq — DSA-4844
7 records Highest priority Priority HIGH 4 HIGH, 3 LOW
Other records, highest priority first
- TI-2020-15698 Heap-based buffer overflow in dnsmasqPriority HIGH 74
- TI-2020-15703 Heap-based buffer overflow in dnsmasqPriority HIGH 69
- TI-2020-15699 Heap-based buffer overflow in dnsmasqPriority HIGH 69
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2021:0150 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.1) | Fixed | RHSA-2021:0152 |
| Red Hat Enterprise Linux AppStream EUS (v. 8.2) | Fixed | RHSA-2021:0151 |
Not affected: 6 products
- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
- Red Hat OpenStack Platform 10 (Newton)
- Red Hat OpenStack Platform 13 (Queens)
Timeline
- 2026-10-02 Threatist record created from CVE-2020-25681
- 2026-10-03 Alias added: GHSA-34v3-rp23-947c
References
Sources
- CVE-2020-25681 · CVE Program
- CVE-2020-25681 · NVD
- FIRST EPSS
- GHSA-34v3-rp23-947c · GitHub Advisory Database · CC BY 4.0
- CVE-2020-25681 · Red Hat security data · CC BY 4.0
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