CVE-2026-104420

Medium

Description

Zebra before 6.3.0 contains a protection mechanism failure that allows unauthenticated peers to evade misbehavior scoring by supplying invalid gossiped blocks. The inbound cleanup step wrongly downcasts RouterError to VerifyBlockError and discards the score, so attackers can repeatedly force block download and Equihash verification without being banned.

SeverityMedium

CVSS5.3

Exploit probability—

ProductZcashfoundation Zebra

PublishedOct 2, 2026

First seenOct 2, 2026

Weakness typeCWE-704CWE-704

How to fix

Update

ZcashFoundation zebra6.3.0 or later

Vendor advisories

github.com/ZcashFoundation/zebra/security/advisories/GHSA-8hh2-hrf2-cqf4

Affected products

Product	Affected versions	Fixed in
ZcashFoundation zebra	v < 6.3.0	6.3.0

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