{"id":"CVE-2026-109366","state":"PUBLISHED","title":"Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height","description":"Zebra before 6.4.0 contains an improper integrity validation vulnerability in the inbound gossip download path that allows unauthenticated peers to force dropping of new blocks without penalty. Attackers can serve a real block with a coinbase scriptSig rewritten to height 1, which keeps the ZIP-244 block hash, triggering a behind-tip drop before consensus validation and delaying tip discovery for mining backends.","publishedAt":"2026-10-12T16:05:43.620Z","updatedAt":"2026-10-26T20:37:40.885Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/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":"6.4.0","versionType":"semver"},{"version":"6.4.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3","https://www.vulncheck.com/advisories/zebra-before-6.4.0-gossiped-block-drop-via-forged-coinbase-scriptsig-height"],"weaknesses":["CWE-354"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/109xxx/CVE-2026-109366.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-109366","state":"PUBLISHED","datePublished":"2026-10-12T16:05:43.620Z","dateUpdated":"2026-10-26T20:37:40.885Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-10-12T14:21:32.595Z"},"containers":{"cna":{"title":"Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height","descriptions":[{"lang":"en","value":"Zebra before 6.4.0 contains an improper integrity validation vulnerability in the inbound gossip download path that allows unauthenticated peers to force dropping of new blocks without penalty. Attackers can serve a real block with a coinbase scriptSig rewritten to height 1, which keeps the ZIP-244 block hash, triggering a behind-tip drop before consensus validation and delaying tip discovery for mining backends."}],"affected":[{"vendor":"ZcashFoundation","product":"zebra","packageURL":"pkg:cargo/zebrad","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"6.4.0","versionType":"semver"},{"version":"6.4.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-4f6v-mj46-gxg3)"},{"url":"https://www.vulncheck.com/advisories/zebra-before-6.4.0-gossiped-block-drop-via-forged-coinbase-scriptsig-height","name":"VulnCheck Advisory: Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","baseScore":3.7,"baseSeverity":"LOW"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-354","lang":"en","description":"Improper Validation of Integrity Check Value","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-10-12T16:05:43.620Z"},"datePublic":"2026-09-28T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:zfnd:zebra:*:*:*:*:*:*:*:*","versionEndExcluding":"6.4.0"}]}]}],"credits":[{"lang":"en","value":"craftsoldier","type":"reporter"},{"lang":"en","value":"arya2","type":"finder"},{"lang":"en","value":"conradoplg","type":"finder"},{"lang":"en","value":"mpguerra","type":"coordinator"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-26T20:37:04.530681Z","id":"CVE-2026-109366","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-26T20:37:40.885Z"}}]}}}