Description
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.
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 |
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 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 |
| Oracle Linux 7 | dnsmasq +1 | 2.76-17.0.3.el7_9.3 | ELSA-2023-12972, ELSA-2023-12971 |
Advisories 17
- 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-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-2023-12971 Important: dnsmasq security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 6, 2023
- ELSA-2023-12972 Important: dnsmasq security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · 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=1882014
- 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