What’s Vulnerable › Vulnerabilities

CVE-2026-104427: Zebra before 6.1.0 Chain Stall via Stale parent_error_map Entry

• 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 2026-10-05
• Weakness: CWE-459

Description

Zebra before 6.1.0 contains an incomplete cleanup vulnerability in the state write task that allows remote unauthenticated peers to stall node synchronization by poisoning parent_error_map. Attackers can deliver a coinbase-malleated block sharing a canonical block's hash before it propagates, causing the next canonical block to be rejected and stalling the node for roughly 2,000 blocks.

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-8gxx-hc65-vv82
• https://www.vulncheck.com/advisories/zebra-before-6.1.0-chain-stall-via-stale-parent-error-map-entry

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