What’s Vulnerable › Vulnerabilities

CVE-2026-104426: Zebra before 6.1.0 Quadratic Complexity DoS via Block Transparent Value Check

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-02 · updated 2026-10-02
• Weakness: CWE-407

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.

Affected products

• ZcashFoundation zebra: before 6.1.0 — fixed in 6.1.0

How to fix

Upgrade to a fixed version: ZcashFoundation zebra 6.1.0. Check the vendor advisory for mitigations.

References

• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-4g24-549m-hp75
• https://www.vulncheck.com/advisories/zebra-before-6.1.0-quadratic-complexity-dos-via-block-transparent-value-check

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