{"id":"CVE-2026-104421","published":"2026-10-02T12:17:12.143","lastModified":"2026-10-02T17:59:09.430","description":"Zebra before 6.2.1 contains an incomplete cleanup vulnerability that allows unauthenticated peers to block downloading of valid blocks by leaving rejected hashes in SentHashes. Attackers can send a contextually invalid block sharing an honest block's header hash, causing Request::KnownBlock to skip the honest block and keep nodes behind the tip.","cvssScore":5.3,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwes":["CWE-459"],"vendors":[],"products":[],"references":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-x93j-mj2f-q338","tags":[]},{"url":"https://www.vulncheck.com/advisories/zebra-before-6.2.1-block-download-denial-of-service-via-knownblock-senthashes-lockout","tags":[]}],"exploitRefs":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-x93j-mj2f-q338","tags":[]}],"hasPoc":true,"ai":null}