{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54478","assignerOrgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","state":"PUBLISHED","assignerShortName":"NLnet Labs","dateReserved":"2026-06-22T12:27:22.817Z","datePublished":"2026-07-22T13:09:18.323Z","dateUpdated":"2026-07-22T14:14:47.347Z"},"containers":{"cna":{"title":"DNS Cookie bypass when combined with proxy-protocol use","datePublic":"2026-07-22T00:00:00.000Z","affected":[{"vendor":"NLnet Labs","product":"Unbound","versions":[{"version":"1.18.0","status":"affected","lessThan":"1.25.2","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"In NLnet Labs Unbound 1.18.0 up to and including 1.25.1, when Unbound listens on a 'proxy-protocol-port' interface with 'answer-cookie: yes', the RFC 9018 server-cookie SipHash is computed over the proxy's wire address instead of the PROXYv2-declared client. One server cookie obtained through a given proxy node therefore validates for every PROXYv2-declared source behind that node. On a UDP+proxy-protocol front, an off-path attacker can harvest one cookie with a single legitimate query, then replay it under any spoofed source and pass DNS Cookie checks that were deployed to defeat this in the first place."}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","baseScore":3.7,"baseSeverity":"LOW","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"}}],"problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-290","description":"CWE-290: Authentication Bypass by Spoofing","type":"CWE"}]}],"solutions":[{"lang":"en","value":"This issue is fixed starting with version 1.25.2"}],"timeline":[{"time":"2026-05-04T00:00:00.000Z","lang":"en","value":"Issue reported by Qifan Zhang"},{"time":"2026-05-29T00:00:00.000Z","lang":"en","value":"NLnet Labs shares patch"},{"time":"2026-05-30T00:00:00.000Z","lang":"en","value":"Qifan Zhang verifies patch"},{"time":"2026-07-22T00:00:00.000Z","lang":"en","value":"Fixes released with version 1.25.2"}],"credits":[{"lang":"en","value":"Qifan Zhang (Palo Alto Networks)","type":"finder"}],"references":[{"url":"https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-54478.txt","tags":["vendor-advisory"]}],"providerMetadata":{"orgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","shortName":"NLnet Labs","dateUpdated":"2026-07-22T13:09:18.323Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-22T14:14:21.553478Z","id":"CVE-2026-54478","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-22T14:14:47.347Z"}}]}}