Answer in brief
CVE-2026-104422 records a High severity (CVSS 8.7) vulnerability in Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite. The current sources do not mark it as known exploited. The current feed maps ZcashFoundation/zebra (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps ZcashFoundation/zebra (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| ZcashFoundation/zebrageneric | >=0 <6.3.0 | 6.3.0 |
Published upstream
Oct 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 2, 2026
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.
Quoted source text, attributed separately from HOL analysis.