EXECUTIVE SUMMARY:
CVE-2026-40880 with a CVSS score of 7.2 is a logic error in Zebra's transaction verification cache that could allow a malicious miner to induce a consensus split by submitting a transaction that is valid for a specific height but invalid at higher heights. The affected product/framework is Zebra, specifically impacted versions prior to 5.0.2 for package zebra-consensus and versions prior to 4.3.1 for package zebrad. An attacker can exploit this vulnerability by submitting a transaction with a specific expiry height, mining a block that contains the same transaction, and submitting the block before the previous one, leading to a chain fork where the poisoned Zebra node is isolated. An attacker gains the capability to induce network partitioning, service disruption, and potential double-spend attacks against affected nodes. The business impact and consequences of this vulnerability include a consensus failure, network partition, and isolation of affected nodes. This vulnerability can be exploited by a malicious miner with access to the network, specifically via a network attack vector.[/subscribe_to_unlock_form]
EXECUTIVE SUMMARY:
CVE-2026-40880 with a CVSS score of 7.2 is a logic error in Zebra's transaction verification cache that could allow a malicious miner to induce a consensus split by submitting a transaction that is valid for a specific height but invalid at higher heights. The affected product/framework is Zebra, specifically impacted versions prior to 5.0.2 for package zebra-consensus and versions prior to 4.3.1 for package zebrad. An attacker can exploit this vulnerability by submitting a transaction with a specific expiry height, mining a block that contains the same transaction, and submitting the block before the previous one, leading to a chain fork where the poisoned Zebra node is isolated. An attacker gains the capability to induce network partitioning, service disruption, and potential double-spend attacks against affected nodes. The business impact and consequences of this vulnerability include a consensus failure, network partition, and isolation of affected nodes. This vulnerability can be exploited by a malicious miner with access to the network, specifically via a network attack vector.[emaillocker id="1283"]
RECOMMENDATION:
We recommend you to update zebra-consensus to version 5.0.2 and zebrad to version 4.3.1.
REFERENCES:
The following reports contain further technical details:
https://github.com/advisories/GHSA-xvj8-ph7x-65gf