{"id":"ALPINE-CVE-2025-5994","details":"A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries to upstream name servers, i.e., at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options is used. Resolvers supporting ECS need to segregate outgoing queries to accommodate for different outgoing ECS information. This re-opens up resolvers to a birthday paradox attack (Rebirthday Attack) that tries to match the DNS transaction ID in order to cache non-ECS poisonous replies.","modified":"2026-03-09T01:22:04.761712Z","published":"2025-07-16T15:15:33.490Z","upstream":["CVE-2025-5994"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2025-5994"}],"affected":[{"package":{"name":"unbound","ecosystem":"Alpine:v3.19","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.0-r2"}]}],"versions":["1.10.0-r0","1.10.1-r0","1.10.1-r1","1.11.0-r0","1.12.0-r0","1.13.0-r0","1.13.0-r1","1.13.0-r2","1.13.0-r3","1.13.1-r0","1.13.1-r1","1.13.1-r2","1.13.2-r0","1.13.2-r1","1.13.2-r2","1.14.0-r0","1.14.0-r1","1.15.0-r0","1.16.0-r0","1.16.0-r1","1.16.1-r0","1.16.2-r0","1.16.2-r1","1.16.3-r0","1.17.0-r0","1.17.0-r1","1.17.1-r0","1.17.1-r1","1.17.1-r2","1.17.1-r3","1.17.1-r4","1.18.0-r0","1.19.0-r0","1.19.1-r0","1.19.2-r0","1.19.3-r0","1.20.0-r0","1.20.0-r1","1.4.10-r0","1.4.10-r1","1.4.10-r2","1.4.10-r3","1.4.13-r0","1.4.13-r1","1.4.13-r2","1.4.13-r3","1.4.14-r0","1.4.15-r0","1.4.16-r0","1.4.17-r0","1.4.18-r0","1.4.19-r0","1.4.19-r1","1.4.19-r2","1.4.20-r0","1.4.20-r1","1.4.20-r2","1.4.21-r0","1.4.21-r1","1.4.21-r2","1.4.22-r0","1.4.22-r1","1.5.1-r0","1.5.10-r0","1.5.10-r1","1.5.10-r2","1.5.2-r0","1.5.2-r1","1.5.3-r0","1.5.4-r0","1.5.6-r0","1.5.6-r1","1.5.6-r2","1.5.6-r3","1.5.6-r4","1.5.7-r0","1.5.7-r1","1.5.8-r0","1.5.8-r1","1.5.9-r0","1.5.9-r1","1.6.0-r0","1.6.0-r1","1.6.1-r0","1.6.1-r1","1.6.2-r0","1.6.3-r0","1.6.4-r0","1.6.5-r0","1.6.6-r0","1.6.7-r0","1.6.7-r1","1.6.7-r2","1.6.8-r0","1.7.0-r0","1.7.0-r1","1.7.0-r2","1.7.1-r0","1.7.3-r0","1.8.0-r0","1.8.1-r0","1.8.1-r1","1.8.3-r0","1.9.0-r0","1.9.1-r0","1.9.1-r1","1.9.1-r2","1.9.2-r0","1.9.2-r1","1.9.3-r0","1.9.4-r0","1.9.4-r1","1.9.5-r0","1.9.5-r1","1.9.5-r2","1.9.5-r3","1.9.6-r0"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2025-5994.json"}},{"package":{"name":"unbound","ecosystem":"Alpine:v3.20","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.20.0-r2"}]}],"versions":["1.10.0-r0","1.10.1-r0","1.10.1-r1","1.11.0-r0","1.12.0-r0","1.13.0-r0","1.13.0-r1","1.13.0-r2","1.13.0-r3","1.13.1-r0","1.13.1-r1","1.13.1-r2","1.13.2-r0","1.13.2-r1","1.13.2-r2","1.14.0-r0","1.14.0-r1","1.15.0-r0","1.16.0-r0","1.16.0-r1","1.16.1-r0","1.16.2-r0","1.16.2-r1","1.16.3-r0","1.17.0-r0","1.17.0-r1","1.17.1-r0","1.17.1-r1","1.17.1-r2","1.17.1-r3","1.17.1-r4","1.18.0-r0","1.19.0-r0","1.19.1-r0","1.19.2-r0","1.19.3-r0","1.19.3-r1","1.19.3-r2","1.20.0-r0","1.20.0-r1","1.4.10-r0","1.4.10-r1","1.4.10-r2","1.4.10-r3","1.4.13-r0","1.4.13-r1","1.4.13-r2","1.4.13-r3","1.4.14-r0","1.4.15-r0","1.4.16-r0","1.4.17-r0","1.4.18-r0","1.4.19-r0","1.4.19-r1","1.4.19-r2","1.4.20-r0","1.4.20-r1","1.4.20-r2","1.4.21-r0","1.4.21-r1","1.4.21-r2","1.4.22-r0","1.4.22-r1","1.5.1-r0","1.5.10-r0","1.5.10-r1","1.5.10-r2","1.5.2-r0","1.5.2-r1","1.5.3-r0","1.5.4-r0","1.5.6-r0","1.5.6-r1","1.5.6-r2","1.5.6-r3","1.5.6-r4","1.5.7-r0","1.5.7-r1","1.5.8-r0","1.5.8-r1","1.5.9-r0","1.5.9-r1","1.6.0-r0","1.6.0-r1","1.6.1-r0","1.6.1-r1","1.6.2-r0","1.6.3-r0","1.6.4-r0","1.6.5-r0","1.6.6-r0","1.6.7-r0","1.6.7-r1","1.6.7-r2","1.6.8-r0","1.7.0-r0","1.7.0-r1","1.7.0-r2","1.7.1-r0","1.7.3-r0","1.8.0-r0","1.8.1-r0","1.8.1-r1","1.8.3-r0","1.9.0-r0","1.9.1-r0","1.9.1-r1","1.9.1-r2","1.9.2-r0","1.9.2-r1","1.9.3-r0","1.9.4-r0","1.9.4-r1","1.9.5-r0","1.9.5-r1","1.9.5-r2","1.9.5-r3","1.9.6-r0"],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/alpine/ALPINE-CVE-2025-5994.json"}},{"package":{"name":"unbound","ecosystem":"Alpine:v3.21","purl":"pkg:apk/alpine/unbound?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.22.0-r1"}]}],"versions":["1.10.0-r0","1.10.1-r0","1.10.1-r1","1.11.0-r0","1.12.0-r0","1.13.0-r0","1.13.0-r1","1.13.0-r2","1.13.0-r3","1.13.1-r0","1.13.1-r1","1.13.1-r2","1.13.2-r0","1.13.2-r1","1.13.2-r2","1.14.0-r0","1.14.0-r1","1.15.0-r0","1.16.0-r0","1.16.0-r1","1.16.1-r0","1.16.2-r0","1.16.2-r1","1.16.3-r0","1.17.0-r0","1.17.0-r1","1.17.1-r0","1.17.1-r1","1.17.1-r2","1.17.1-r3","1.17.1-r4","1.18.0-r0","1.19.0-r0","1.19.1-r0","1.19.2-r0","1.19.3-r0","1.19.3-r1","1.19.3-r2","1.20.0-r0","1.20.0-r1","1.20.0-r2","1.21.0-r0","1.21.1-r0","1.22.0-r0","1.4.10-r0","1.4.10-r1","1.4.10-r2","1.4.10-r3","1.4.13-r0","1.4.13-r1","1.4.13-r2","1.4.13-r3","1.4.14-r0","1.4.15-r0","1.4.16-r0","1.4.17-r0","1.4.18-r0","1.4.19-r0","1.4.19-r1","1.4.19-r2","1.4.20-r0","1.4.20-r1","1.4.20-r2","1.4.21-r0","1.4.21-r1","1.4.21-r2","1.4.22-r0","1.4.22-r1","1.5.1-r0","1.5.10-r0","1.5.10-r1","1.5.10-r2","1.5.2-r0","1.5.2-r1","1.5.3-r0","1.5.4-r0","1.5.6-r0","1.5.6-r1","1.5.6-r2","1.5.6-r3","1.5.6-r4","1.5.7-r0","1.5.7-r1","1.5.8-r0","1.5.8-r1","1.5.9-r0","1.5.9-r1","1.6.0-r0","1.6.0-r1","1.6.1-r0","1.6.1-r1","1.6.2-r0","1.6.3-r0","1.6.4-r0","1.6.5-r0","1.6.6-r0","1.6.7-r0","1.6.7-r1","1.6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