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Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite

Type: advisorySource: Official CVE List1 source record

The block sync download path in Zebra (zebrad) before 6.3.0 reads a block's height from its unvalidated coinbase scriptSig and drops blocks that appear too far behind the tip before consensus validation, without penalizing the supplying peer. Because V5 transaction IDs exclude the scriptSig, a malicious peer can repeatedly serve a canonical block whose coinbase claims height 1 while keeping the requested hash, delaying the node's discovery of the newest block.

Announced Source revision 1
Original source ↗

CVE-2026-104422

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-104422

zebra

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "vendor": "ZcashFoundation",
    "product": "zebra",
    "versions": [
      {
        "status": "affected",
        "version": "0",
        "lessThan": "6.3.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.3.0",
        "versionType": "semver"
      }
    ],
    "packageURL": "pkg:cargo/Zebrad",
    "defaultStatus": "unaffected"
  }
]
Related CVEs
CVE-2026-104422

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#8065 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement