What’s Vulnerable › Vulnerabilities
CVE-2026-40880: Zebra: Cached Mempool Verification Bypasses Consensus Rules for Ahead-of-Tip Blocks
- Severity: high (CVSS 8.1 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: 2026-04-21 · updated 2026-10-26
- Weakness: CWE-1025
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to zebrad version 4.3.1 and zebra-consensus version 5.0.2, a logic error in Zebra's transaction verification cache could allow a malicious miner to induce a consensus split. By carefully submitting a transaction that is valid for height H+1 but invalid for H+2 and then mining that transaction in a block at height H+2, a miner could cause vulnerable Zebra nodes to accept an invalid block, leading to a consensus split from the rest of the Zcash network. This vulnerability is fixed in zebrad version 4.3.1 and zebra-consensus version 5.0.2.
Affected products
- ZcashFoundation zebra-consensus: before 5.0.2 — fixed in 5.0.2
- ZcashFoundation zebra: before 4.3.1 — fixed in 4.3.1
How to fix
Upgrade to a fixed version: ZcashFoundation zebra-consensus 5.0.2; ZcashFoundation zebra 4.3.1. Check the vendor advisory for mitigations.
References
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