Description
A flaw was found in dnsmasq in versions before 2.85. When configured to use a specific server for a given network interface, dnsmasq uses a fixed port while forwarding queries. An attacker on the network, able to find the outgoing port used by dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this vulnerability is to data integrity.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | dnsmasq | dnsmasq 2.85 | — |
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 | 2.85-1 | — |
| Debian 13 | dnsmasq | 2.85-1 | — |
| Debian 12 | dnsmasq | 2.85-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | dnsmasq | 2.80-1.1ubuntu1.4 | USN-4976-1 |
| Ubuntu 18.04 LTS | dnsmasq | 2.79-1ubuntu0.4 | USN-4976-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | dnsmasq | 2.79-1ubuntu0.16.04.1+esm1 | USN-4976-2 |
| Ubuntu Pro 14.04 LTS | dnsmasq | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | dnsmasq +1 | 2.79-19.el8 | RHSA-2021:4153 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | dnsmasq +1 | 2.79-19.el8 | ALSA-2021:4153 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | dnsmasq | 2.79-19.el8 | RLSA-2021:4153 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLES 15 SP2 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLES 15 SP1 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLES 15 | dnsmasq | 2.78-150000.3.14.1 | SUSE-SU-2022:1288-1 |
| SLES 12 SP5 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
Show 20 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLES 12 SP3 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLES 12 SP2 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLES 11 SP4 | dnsmasq | 2.78-0.17.18.1 | SUSE-SU-2022:14941-1 |
| SLES for SAP 15 SP1 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLES for SAP 15 | dnsmasq | 2.78-150000.3.14.1 | SUSE-SU-2022:1288-1 |
| SLES for SAP 12 SP5 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLES for SAP 12 SP4 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLES for SAP 12 SP3 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SLE Micro 5.1 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLE Micro 5.0 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLE HPC 15 SP1 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
| SLE HPC 15 | dnsmasq | 2.78-150000.3.14.1 | SUSE-SU-2022:1288-1 |
| SUSE OpenStack Cloud Crowbar 9 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SUSE OpenStack Cloud Crowbar 8 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SUSE OpenStack Cloud 9 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SUSE OpenStack Cloud 8 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | dnsmasq | 2.78-0.16.17.1 | SUSE-SU-2022:14940-1 |
| SUSE HPE Helion OpenStack 8 | dnsmasq | 2.78-18.18.1 | SUSE-SU-2022:1289-1 |
| SUSE Enterprise Storage 6 | dnsmasq | 2.86-7.14.1 | SUSE-SU-2021:3530-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dnsmasq | 2.86-1.1 | openSUSE-SU-2024:10721-1 |
| openSUSE Leap 15.3 | dnsmasq | 2.86-7.14.1 | openSUSE-SU-2021:3530-1 |
| openSUSE Leap 15.2 | dnsmasq | 2.86-lp152.7.6.1 | openSUSE-SU-2021:1426-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dnsmasq | 2.85-r0 | — |
| Alpine v3.23 | dnsmasq | 2.85-r0 | — |
| Alpine v3.22 | dnsmasq | 2.85-r0 | — |
| Alpine v3.21 | dnsmasq | 2.85-r0 | — |
| Alpine v3.20 | dnsmasq | 2.85-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | dnsmasq | 2.85-r0 | — |
| Alpine v3.18 | dnsmasq | 2.85-r0 | — |
| Alpine v3.17 | dnsmasq | 2.85-r0 | — |
| Alpine v3.16 | dnsmasq | 2.85-r0 | — |
| Alpine v3.15 | dnsmasq | 2.85-r0 | — |
| Alpine v3.14 | dnsmasq | 2.85-r0 | — |
| Alpine v3.13 | dnsmasq | 2.85-r0 | — |
| Alpine v3.12 | dnsmasq | 2.85-r0 | — |
| Alpine v3.11 | dnsmasq | 2.85-r0 | — |
| Alpine v3.10 | dnsmasq | 2.85-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | dnsmasq +1 | 2.79-19.el8 | ELSA-2021-4153 |
Advisories 15
- ALSA-2021:4153 Moderate: dnsmasq security and bug fix update AlmaLinux Security Advisories · Oct 29, 2026
- USN-4976-2 dnsmasq vulnerability Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-4976-1 dnsmasq vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026
- RLSA-2021:4153 Moderate: dnsmasq security and bug fix update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2021:1426-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:14941-1 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
- SUSE-SU-2022:1288-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:1289-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3530-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:14940-1 Security update for dnsmasq SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:4153 Red Hat Security Advisory: dnsmasq security and bug fix update Red Hat Security Advisories (RHSA) · Dec 3, 2025
- WID-SEC-2022-1335 Xerox FreeFlow Print Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 6, 2025
- openSUSE-SU-2021:3530-1 Security update for dnsmasq SUSE / openSUSE Security Updates · May 7, 2025
- ELSA-2021-4153 Moderate: dnsmasq security and bug fix update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 16, 2021
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1939368
- FEDORA-2021-62a5062b2d vendor-advisory
- FEDORA-2021-9433bedebd vendor-advisory
- FEDORA-2021-5cd2571751 vendor-advisory
- GLSA-202105-20 vendor-advisory
- https://www.oracle.com/security-alerts/cpujan2022.html