Description
A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | dnsmasq | dnsmasq 2.83 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | dnsmasq | 2.83-1 | — |
| Debian 13 | dnsmasq | 2.83-1 | — |
| Debian 12 | dnsmasq | 2.83-1 | — |
| Debian 10 | dnsmasq | 2.80-1+deb10u1 | DSA-4844-1 |
| Debian 9 | dnsmasq | 2.76-5+deb9u3 | DLA-2604-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | dnsmasq | 2.80-1.1ubuntu1.2 | USN-4698-1 |
| Ubuntu 18.04 LTS | dnsmasq | 2.79-1ubuntu0.2 | USN-4698-1 |
| Ubuntu 16.04 LTS | dnsmasq | 2.75-1ubuntu0.16.04.7 | USN-4698-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | dnsmasq | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | dnsmasq +1 | 2.79-13.el8_3.1 | RHSA-2021:0150 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | dnsmasq +1 | 2.79-11.el8_2.2 | RHSA-2021:0151 |
| RHEL 8.1 EUS | dnsmasq +1 | 2.79-6.el8_1.1 | RHSA-2021:0152 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | dnsmasq | 2.78-7.6.1 | SUSE-SU-2021:0163-1 |
| SLES 15 SP1 | dnsmasq | 2.78-7.6.1 | SUSE-SU-2021:0163-1 |
| SLES 15 | dnsmasq | 2.78-3.11.1 | SUSE-SU-2021:0162-1 |
| SLES 12 SP5 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES 12 SP4 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
Show 17 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES 12 SP2 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES 11 SP4 | dnsmasq | 2.78-0.17.15.1 | SUSE-SU-2021:14603-1 |
| SLES for SAP 15 | dnsmasq | 2.78-3.11.1 | SUSE-SU-2021:0162-1 |
| SLES for SAP 12 SP5 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES for SAP 12 SP4 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES for SAP 12 SP3 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLES for SAP 12 SP2 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SLE HPC 15 | dnsmasq | 2.78-3.11.1 | SUSE-SU-2021:0162-1 |
| SUSE OpenStack Cloud Crowbar 9 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE OpenStack Cloud Crowbar 8 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE OpenStack Cloud 9 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE OpenStack Cloud 8 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE OpenStack Cloud 7 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | dnsmasq | 2.78-0.16.14.1 | SUSE-SU-2021:14604-1 |
| SUSE HPE Helion OpenStack 8 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
| SUSE Enterprise Storage 5 | dnsmasq | 2.78-18.15.1 | SUSE-SU-2021:0166-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dnsmasq | 2.86-1.1 | openSUSE-SU-2024:10721-1 |
| openSUSE Leap 15.2 | dnsmasq | 2.78-lp152.7.3.1 | openSUSE-SU-2021:0124-1 |
| openSUSE Leap 15.1 | dnsmasq | 2.78-lp151.5.6.1 | openSUSE-SU-2021:0129-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dnsmasq | 2.83-r0 | — |
| Alpine v3.23 | dnsmasq | 2.83-r0 | — |
| Alpine v3.22 | dnsmasq | 2.83-r0 | — |
| Alpine v3.21 | dnsmasq | 2.83-r0 | — |
| Alpine v3.20 | dnsmasq | 2.83-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | dnsmasq | 2.83-r0 | — |
| Alpine v3.18 | dnsmasq | 2.83-r0 | — |
| Alpine v3.17 | dnsmasq | 2.83-r0 | — |
| Alpine v3.16 | dnsmasq | 2.83-r0 | — |
| Alpine v3.15 | dnsmasq | 2.83-r0 | — |
| Alpine v3.14 | dnsmasq | 2.83-r0 | — |
| Alpine v3.13 | dnsmasq | 2.83-r0 | — |
| Alpine v3.12 | dnsmasq | 2.83-r0 | — |
| Alpine v3.11 | dnsmasq | 2.83-r0 | — |
| Alpine v3.10 | dnsmasq | 2.83-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | dnsmasq +1 | 2.79-13.el8_3.1 | ELSA-2021-0150 |
Advisories 16
- RHSA-2021:0152 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0151 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0150 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- DSA-4844-1 dnsmasq - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2604-1 dnsmasq - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4698-1 dnsmasq vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- SUSE-SU-2021:0162-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0163-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14604-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0124-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10721-1 dnsmasq-2.86-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0129-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14603-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:0166-1 Security update for dnsmasq SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2023-2836 dnsmasq: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 6, 2023
- ELSA-2021-0150 Important: dnsmasq security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 20, 2021
References
- https://www.jsof-tech.com/disclosures/dnspooq/
- https://bugzilla.redhat.com/show_bug.cgi?id=1882018
- FEDORA-2021-84440e87ba vendor-advisory
- GLSA-202101-17 vendor-advisory
- DSA-4844 vendor-advisory
- FEDORA-2021-2e4c3d5a9d vendor-advisory
- [debian-lts-announce] 20210322 [SECURITY] [DLA 2604-1] dnsmasq security update mailing-list