Description
Zebra zebrad 4.5.0 and zebra-script 7.0.0 count P2SH redeem script signature operations in legacy mode rather than zcashd's accurate P2SH mode, overcounting CHECKMULTISIG preceded by OP_1 through OP_16 as 20 sigops and causing a consensus divergence. Remote attackers can broadcast P2SH spends using low-threshold multisig redeem scripts so that a block zcashd accepts exceeds Zebra's inflated MAX_BLOCK_SIGOPS count, causing Zebra nodes to reject it and stall off the chain.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| ZcashFoundation | zebra | 4.5.0 – < 4.5.1, 7.0.0 – < 7.0.1 | 4.5.1 |
References
- GitHub Security Advisory (GHSA-2prc-cj5x-4443) vendor-advisory
- VulnCheck Advisory: Zebra 4.5.0 Consensus Split via P2SH Sigop Overcount third-party-advisory