{"id":"CVE-2026-104420","title":"Zebra before 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks","summary":"Zebra before 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks. The inbound cleanup step wrongly downcasts RouterError to VerifyBlockError an…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","cwe":["CWE-704"],"vendor":"ZcashFoundation","product":"zebra","affected":["zebra < 6.3.0"],"published":"2026-10-02","updated":"2026-10-02","sourceUpdated":"2026-10-02T12:17:11.997","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-104420","references":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-8hh2-hrf2-cqf4","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/zebra-before-6.3.0-peer-misbehavior-ban-bypass-via-gossiped-blocks","label":"disclosure@vulncheck.com"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-02T12:17:44.329Z","slug":"CVE-2026-104420","body":"## Overview\n\nZebra before 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks. The inbound cleanup step wrongly downcasts RouterError to VerifyBlockError and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}