CVE-2026-40880 PUBLISHED

Zebra: Cached Mempool Verification Bypasses Consensus Rules for Ahead-of-Tip Blocks

Assigner: GitHub_M
Reserved: 15.04.2026 Published: 21.04.2026 Updated: 21.04.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H
CVSS Score: 7.2

Product Status

Vendor ZcashFoundation
Product zebrad
Versions
  • Version < 4.3.1 is affected
Vendor ZcashFoundation
Product zebra-consensus
Versions
  • Version < 5.0.2 is affected

References

Problem Types

  • CWE-1025: Comparison Using Wrong Factors CWE