{"id":"CVE-2026-104420","state":"PUBLISHED","title":"Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks","description":"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 and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned.","publishedAt":"2026-10-02T11:38:01.836Z","updatedAt":"2026-10-06T02:37:15.210Z","severity":{"score":6.9,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["ZcashFoundation zebra"],"affected":[{"vendor":"ZcashFoundation","product":"zebra","packageURL":"pkg:cargo/zebrad","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.3.0","versionType":"semver"},{"version":"6.3.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-8hh2-hrf2-cqf4","https://www.vulncheck.com/advisories/zebra-before-6.3.0-peer-misbehavior-ban-bypass-via-gossiped-blocks"],"weaknesses":["CWE-704"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/104xxx/CVE-2026-104420.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-104420","state":"PUBLISHED","datePublished":"2026-10-02T11:38:01.836Z","dateUpdated":"2026-10-06T02:37:15.210Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-10-02T00:46:23.830Z"},"containers":{"cna":{"title":"Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks","descriptions":[{"lang":"en","value":"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 and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned."}],"affected":[{"vendor":"ZcashFoundation","product":"zebra","packageURL":"pkg:cargo/zebrad","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.3.0","versionType":"semver"},{"version":"6.3.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-8hh2-hrf2-cqf4","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-8hh2-hrf2-cqf4)"},{"url":"https://www.vulncheck.com/advisories/zebra-before-6.3.0-peer-misbehavior-ban-bypass-via-gossiped-blocks","name":"VulnCheck Advisory: Zebra before 6.3.0 Peer Misbehavior Ban Bypass via Gossiped Blocks","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","baseScore":5.3,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-704","lang":"en","description":"Incorrect Type Conversion or Cast","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-10-02T11:38:01.836Z"},"datePublic":"2026-08-11T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:*","versionEndExcluding":"6.3.0"}]}]}],"credits":[{"lang":"en","value":"evan-forbes","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-06T02:37:04.929175Z","id":"CVE-2026-104420","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-06T02:37:15.210Z"}}]}}}