Description
A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. 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 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
knqyf263/dnspooq ★ 101 · Jan 23, 2021
DNSpooq - dnsmasq cache poisoning (CVE-2020-25686, CVE-2020-25684, CVE-2020-25685)
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
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=1890125
- 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