Zebra 6.4.0 before 6.4.2 Denial of Service via Malformed v6 Transaction
Published Oct 12, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Zebra 6.4.0 before 6.4.2 Denial of Service via Malformed v6 Transaction
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
ZcashFoundation Zebra 6.4.0 before 6.4.2 parses version 6 transactions carrying a pre-NU6.3 consensus branch ID, but the size computation during UnminedTx construction treats re-serialization of the Orchard bundle as infallible, so the resulting error trips an expect that aborts zebrad. Unauthenticated peers can send a single pre-handshake tx message to crash the node, and can repeat this after each restart.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- Patch commit ↗
- VulnCheck Advisory: Zebra 6.4.0 before 6.4.2 Denial of Service via Malformed v6 Transaction ↗
Record history
Published Oct 12, 2026 · Last refreshed Nov 3, 2026