{"id":"ALPINE-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":"2026-03-09T01:17:20.846014Z","published":"2021-01-20T16:15:14.303Z","upstream":["CVE-2020-25685"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2020-25685"}],"affected":[{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.10","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"versions":["2.46-r0","2.47-r0","2.49-r0","2.50-r0","2.50-r1","2.51-r0","2.52-r0","2.52-r1","2.55-r0","2.57-r0","2.58-r0","2.59-r0","2.59-r1","2.60-r0","2.61-r0","2.62-r0","2.63-r0","2.64-r0","2.65-r0","2.66-r0","2.66-r1","2.66-r2","2.67-r0","2.68-r0","2.69-r0","2.70-r0","2.71-r0","2.72-r0","2.72-r1","2.73-r0","2.75-r0","2.75-r1","2.75-r2","2.76-r0","2.76-r1","2.76-r2","2.76-r3","2.76-r4","2.77-r0","2.78-r0","2.78-r1","2.78-r2","2.79-r0","2.79-r1","2.79-r2","2.80-r0","2.80-r1","2.80-r2","2.80-r3","2.80-r4"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.11","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"versions":["2.46-r0","2.47-r0","2.49-r0","2.50-r0","2.50-r1","2.51-r0","2.52-r0","2.52-r1","2.55-r0","2.57-r0","2.58-r0","2.59-r0","2.59-r1","2.60-r0","2.61-r0","2.62-r0","2.63-r0","2.64-r0","2.65-r0","2.66-r0","2.66-r1","2.66-r2","2.67-r0","2.68-r0","2.69-r0","2.70-r0","2.71-r0","2.72-r0","2.72-r1","2.73-r0","2.75-r0","2.75-r1","2.75-r2","2.76-r0","2.76-r1","2.76-r2","2.76-r3","2.76-r4","2.77-r0","2.78-r0","2.78-r1","2.78-r2","2.79-r0","2.79-r1","2.79-r2","2.80-r0","2.80-r1","2.80-r2","2.80-r3","2.80-r4","2.80-r5"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.12","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"versions":["2.46-r0","2.47-r0","2.49-r0","2.50-r0","2.50-r1","2.51-r0","2.52-r0","2.52-r1","2.55-r0","2.57-r0","2.58-r0","2.59-r0","2.59-r1","2.60-r0","2.61-r0","2.62-r0","2.63-r0","2.64-r0","2.65-r0","2.66-r0","2.66-r1","2.66-r2","2.67-r0","2.68-r0","2.69-r0","2.70-r0","2.71-r0","2.72-r0","2.72-r1","2.73-r0","2.75-r0","2.75-r1","2.75-r2","2.76-r0","2.76-r1","2.76-r2","2.76-r3","2.76-r4","2.77-r0","2.78-r0","2.78-r1","2.78-r2","2.79-r0","2.79-r1","2.79-r2","2.80-r0","2.80-r1","2.80-r2","2.80-r3","2.80-r4","2.80-r5","2.81-r0"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.13","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"versions":["2.46-r0","2.47-r0","2.49-r0","2.50-r0","2.50-r1","2.51-r0","2.52-r0","2.52-r1","2.55-r0","2.57-r0","2.58-r0","2.59-r0","2.59-r1","2.60-r0","2.61-r0","2.62-r0","2.63-r0","2.64-r0","2.65-r0","2.66-r0","2.66-r1","2.66-r2","2.67-r0","2.68-r0","2.69-r0","2.70-r0","2.71-r0","2.72-r0","2.72-r1","2.73-r0","2.75-r0","2.75-r1","2.75-r2","2.76-r0","2.76-r1","2.76-r2","2.76-r3","2.76-r4","2.77-r0","2.78-r0","2.78-r1","2.78-r2","2.79-r0","2.79-r1","2.79-r2","2.80-r0","2.80-r1","2.80-r2","2.80-r3","2.80-r4","2.80-r5","2.81-r0","2.81-r1","2.82-r0"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.14","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"versions":["2.46-r0","2.47-r0","2.49-r0","2.50-r0","2.50-r1","2.51-r0","2.52-r0","2.52-r1","2.55-r0","2.57-r0","2.58-r0","2.59-r0","2.59-r1","2.60-r0","2.61-r0","2.62-r0","2.63-r0","2.64-r0","2.65-r0","2.66-r0","2.66-r1","2.66-r2","2.67-r0","2.68-r0","2.69-r0","2.70-r0","2.71-r0","2.72-r0","2.72-r1","2.73-r0","2.75-r0","2.75-r1","2.75-r2","2.76-r0","2.76-r1","2.76-r2","2.76-r3","2.76-r4","2.77-r0","2.78-r0","2.78-r1","2.78-r2","2.79-r0","2.79-r1","2.79-r2","2.80-r0","2.80-r1","2.80-r2","2.80-r3","2.80-r4","2.80-r5","2.81-r0","2.81-r1","2.82-r0"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.15","purl":"pkg:apk/alpine/dnsmasq?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.83-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2020-25685.json"}},{"package":{"name":"dnsmasq","ecosystem":"Alpine:v3.16","purl":"pkg:apk/alpine/dnsmasq?arch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