A critical consensus vulnerability in the Zebra Zcash node software may lead to network splits and potential transaction validation failures.

This is a consensus-level vulnerability involving improper error handling of invalid sighash types during signature validation, which allows an attacker to bypass intended rejection logic and potentially force a consensus split.

Successful exploitation poses a significant risk to the integrity of the Zcash node network, potentially leading to chain forks or denial-of-service for specific nodes. Given the CVSS score of 9.1, this flaw threatens the operational continuity of financial systems relying on Zebra nodes.

Immediate Action: Upgrade all instances of zebrad to version 4.4.0 and zebra-script to version 6.0.0 immediately.

Proactive Monitoring: Monitor node logs for synchronization errors or unexpected consensus-related warnings that deviate from standard operating parameters.

Compensating Controls: Ensure nodes are behind robust firewalls and restrict peer-to-peer connections to trusted, known entities only.

Public Exploit Available: No

This vulnerability represents a significant risk to blockchain consensus integrity. Organizations running Zebra nodes must prioritize the update to the patched versions to prevent network-level disruption and ensure continued compatibility with the Zcash network.