{"id":"CVE-2020-25685","details":"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.","modified":"2026-03-13T00:36:58.125891Z","published":"2021-01-20T16:15:14.303Z","related":["MGASA-2021-0059","SUSE-SU-2021:0162-1","SUSE-SU-2021:0163-1","SUSE-SU-2021:0166-1","SUSE-SU-2021:14603-1","SUSE-SU-2021:14604-1","openSUSE-SU-2021:0124-1","openSUSE-SU-2021:0129-1","openSUSE-SU-2024:10721-1"],"references":[{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGB7HL3OWHTLEPSMLDGOMXQKG3KM2QME/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WYW3IR6APUSKOYKL5FT3ACTIHWHGQY32/"},{"type":"WEB","url":"https://www.kb.cert.org/vuls/id/434904"},{"type":"ADVISORY","url":"https://security.gentoo.org/glsa/202101-17"},{"type":"ADVISORY","url":"https://www.arista.com/en/support/advisories-notices/security-advisories/12135-security-advisory-61"},{"type":"ADVISORY","url":"https://www.debian.org/security/2021/dsa-4844"},{"type":"ADVISORY","url":"https://www.jsof-tech.com/disclosures/dnspooq/"},{"type":"FIX","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1889688"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2020-25685.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"fixed":"2.83"}]},{"events":[{"introduced":"0"},{"last_affected":"32"}]},{"events":[{"introduced":"0"},{"last_affected":"33"}]},{"events":[{"introduced":"0"},{"last_affected":"10.0"}]},{"events":[{"introduced":"4.21"},{"fixed":"4.21.14m"}]},{"events":[{"introduced":"4.22"},{"fixed":"4.22.9m"}]},{"events":[{"introduced":"4.23"},{"fixed":"4.23.7m"}]},{"events":[{"introduced":"4.24"},{"fixed":"4.24.5m"}]},{"events":[{"introduced":"4.25"},{"fixed":"4.25.2f"}]},{"events":[{"introduced":"0"},{"fixed":"2.83"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}