CVE-2026-104422 — Zebra before 6.3.0 Block Sync Denial of Service via Coinbase scriptSig Rewrite
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 be…
Published: 2026-10-02 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7