Low severity3.7NVD Advisory· Published Jan 20, 2021· Updated Jun 17, 2026
CVE-2020-25686
CVE-2020-25686
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.
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Affected products
35cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:*range: <2.83
- (no CPE)range: <2.83
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
- dnsmasq/dnsmasqdescription
- osv-coords28 versionspkg:rpm/opensuse/dnsmasq&distro=openSUSE%20Leap%2015.1pkg:rpm/opensuse/dnsmasq&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/dnsmasq&distro=openSUSE%20Tumbleweedpkg:rpm/suse/dnsmasq&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/dnsmasq&distro=SUSE%20Enterprise%20Storage%205pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-ESPOSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP1pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Basesystem%2015%20SP2pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Point%20of%20Sale%2011%20SP3pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCLpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%2015-LTSSpkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP2pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/dnsmasq&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015pkg:rpm/suse/dnsmasq&distro=SUSE%20OpenStack%20Cloud%207pkg:rpm/suse/dnsmasq&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/suse/dnsmasq&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/dnsmasq&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/dnsmasq&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209
< 2.78-lp151.5.6.1+ 27 more
- (no CPE)range: < 2.78-lp151.5.6.1
- (no CPE)range: < 2.78-lp152.7.3.1
- (no CPE)range: < 2.86-1.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-3.11.1
- (no CPE)range: < 2.78-3.11.1
- (no CPE)range: < 2.78-7.6.1
- (no CPE)range: < 2.78-7.6.1
- (no CPE)range: < 2.78-0.16.14.1
- (no CPE)range: < 2.78-0.17.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-3.11.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-3.11.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
- (no CPE)range: < 2.78-18.15.1
Patches
Vulnerability mechanics
References
8- bugzilla.redhat.com/show_bug.cginvdIssue TrackingPatchThird Party Advisory
- security.gentoo.org/glsa/202101-17nvdThird Party Advisory
- www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61nvdThird Party Advisory
- www.debian.org/security/2021/dsa-4844nvdThird Party Advisory
- www.jsof-tech.com/disclosures/dnspooq/nvdThird Party Advisory
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/nvd
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/nvd
- www.kb.cert.org/vuls/id/434904nvd
News mentions
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