Description
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
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 |
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 |
| RHEL 7 | dnsmasq +1 | 2.76-16.el7_9.1 | RHSA-2021:0153 |
| RHEL 7 | redhat-virtualization-host +1 | 4.3.13-20210127.0.el7_9 | RHSA-2021:0395 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhev Hypervisor 4 | redhat-virtualization-host +1 | 4.4.4-20210201.0.el8_3 | RHSA-2021:0401 |
| 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 |
| RHEL 7.7 EUS | dnsmasq +1 | 2.76-10.el7_7.2 | RHSA-2021:0154 |
| RHEL 7.6 EUS | dnsmasq +1 | 2.76-7.el7_6.2 | RHSA-2021:0155 |
| RHEL 7.4 TUS | dnsmasq +1 | 2.76-2.el7_4.3 | RHSA-2021:0156 |
| RHEL 7.4 E4S | dnsmasq +1 | 2.76-2.el7_4.3 | RHSA-2021:0156 |
| RHEL 7.4 AUS | dnsmasq +1 | 2.76-2.el7_4.3 | RHSA-2021:0156 |
| RHEL 7.3 AUS | dnsmasq +1 | 2.66-21.el7_3.3 | RHSA-2021:0245 |
| RHEL 7.2 AUS | dnsmasq +1 | 2.66-14.el7_2.3 | RHSA-2021:0240 |
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 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | dnsmasq +1 | 2.76-16.amzn2.1.1 | ALAS2-2021-1587 |
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 | 2.76-16.el7_9.1 | ELSA-2021-0153 |
Advisories 28
- RHSA-2021:0401 Red Hat Security Advisory: Red Hat Virtualization Host security bug fix and enhancement update [ovirt-4.4.4] Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0395 Red Hat Security Advisory: RHV-H security, bug fix, enhancement update (redhat-virtualization-host) 4.3.13 Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0245 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0240 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0156 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0154 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0155 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0152 Red Hat Security Advisory: dnsmasq security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:0153 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
- 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
- VDE-2021-012 MB connect line: multiple products partially affected by DNSpooq CERT@VDE · May 14, 2025
- ICSA-21-019-01 dnsmasq by Simon Kelley (Update A) CISA ICS & IT advisories · May 6, 2025
- 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
- SSA-646763 SSA-646763: DNSpooq - Dnsmasq Vulnerabilities in SCALANCE and RUGGEDCOM Devices Siemens ProductCERT · May 11, 2021
- ALAS2-2021-1587 Moderate: dnsmasq security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jan 26, 2021
- ELSA-2021-0150 Important: dnsmasq security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jan 20, 2021
- ELSA-2021-0153 Moderate: dnsmasq security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jan 19, 2021
References
- https://www.jsof-tech.com/disclosures/dnspooq/
- https://bugzilla.redhat.com/show_bug.cgi?id=1889688
- FEDORA-2021-84440e87ba vendor-advisory
- GLSA-202101-17 vendor-advisory
- DSA-4844 vendor-advisory
- FEDORA-2021-2e4c3d5a9d vendor-advisory
- https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61