Zebra v4.4.0 contains a critical consensus vulnerability related to ZIP-244 enforcement for V5 transparent transactions. Specifically, it fails to reject transactions where an input signed with SIGHASH_SINGLE has no corresponding transparent output at the same index, causing Zebra to accept transactions that zcashd rejects. This discrepancy can lead to network partitioning and consensus splits. The issue is fixed in Zebra 4.4.1.