CVE-2026-104426

Medium

Description

Zebra before 6.1.0 contains an inefficient algorithmic complexity vulnerability in remaining_transaction_value that clones the entire block-level spent-UTXO map per transaction during contextual verification. Attackers can mine or seed the mempool with roughly 26,000 minimal single-input transactions in one block, stalling every validating node for over 52 seconds.

SeverityMedium

CVSS5.9

Exploit probability—

ProductZcashfoundation Zebra

PublishedOct 2, 2026

First seenOct 2, 2026

Weakness typeCWE-407CWE-407

How to fix

Update

ZcashFoundation zebra6.1.0 or later

Vendor advisories

github.com/ZcashFoundation/zebra/security/advisories/GHSA-4g24-549m-hp75

Affected products

Product	Affected versions	Fixed in
ZcashFoundation zebra	v < 6.1.0	6.1.0

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