CVE-2026-109366

Low

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.

SeverityLow

CVSS3.7

Exploit probability—

ProductZcashfoundation Zebra

PublishedOct 12, 2026

First seenOct 12, 2026

Weakness typeCWE-354CWE-354

How to fix

Update

ZcashFoundation zebra6.4.0 or later

Vendor advisories

github.com/ZcashFoundation/zebra/security/advisories/GHSA-4f6v-mj46-gxg3

Affected products

Product	Affected versions	Fixed in
ZcashFoundation zebra	v < 6.4.0	6.4.0

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