High severity · published Apr 21, 2026
CVE-2026-40880
Zebra: Cached Mempool Verification Bypasses Consensus Rules for Ahead-of-Tip Blocks
8.1
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 18% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ZE
zebra-consensus · ZcashFoundation
< 5.0.2 · source: vendor, NVD
ZE
zebrad · ZcashFoundation
< 4.3.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40880
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40880
Vendor Advisory
https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-xvj8-ph7x-65gf
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