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Low · 3.7 CVE-2026-109366 EUVD-2026-97668GHSA-mprq-2cjh-7qc2

Zebra before 6.4.0 Gossiped Block Drop via Forged Coinbase scriptSig Height

Published Oct 12, 2026 · Updated Oct 26, 2026 · Assigned by VulnCheck

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.

Affected products

VendorProductAffectedFixed
ZcashFoundation zebra < 6.4.0 6.4.0

References