CVE-2021-45699: Nervos Ckb

High severity, CVSS 7.5. EPSS: 1.5% chance of exploitation in the next 30 days.

An issue was discovered in the ckb crate before 0.40.0 for Rust. Remote attackers may be able to conduct a 51% attack against the Nervos CKB blockchain by triggering an inability to allocate memory for the misbehavior HashMap.

Affected products

• Nervos Ckb: before 0.40.0 (fixed in 0.40.0)

Published 2021-12-27. Last modified 2026-06-17.