RUSTSEC-2021-0108: Remote memory exhaustion in ckb

What to do

1. See which version you have: cargo tree -i ckb (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p ckb. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example ckb = "0.40.0") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

In the ckb sync protocol, SyncState maintains a HashMap called 'misbehavior' that keeps a score of a peer's violations of the protocol. This HashMap is keyed to PeerIndex (an alias for SessionId), and entries are never removed from it. SessionId is an integer that increases monotonically with every new connection.

A remote attacker can manipulate this HashMap to grow forever, resulting in degraded performance and ultimately a panic on allocation failure or being killed by the OS, depending on the platform.

This is a critical severity security bug. It could be exploited to create a targeted or network-wide denial of service, to reduce the hash power of the network as part of a 51% attack, and perhaps in other creative ways.

References

• Package: crates.io/crates/ckb
• Advisory: rustsec.org/advisories/RUSTSEC-2021-0108.html

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.

Other advisories for ckb

• VulnerabilityRUSTSEC-2021-0107 · 2021-07-25Miner fails to get block template when a cell used as a cell dep has been destroyed.
• VulnerabilityRUSTSEC-2021-0109 · 2021-07-25Process crashes when the cell used as DepGroup is not alive
• VulnerabilityGHSA-29c2-65rj-h343 · 2024-02-03Nervos CKB Permit load cell data from memory
• VulnerabilityGHSA-29c2-65rj-h343 · 2024-02-03Nervos CKB Permit load cell data from memory
• VulnerabilityGHSA-29c2-65rj-h343 · 2024-02-03Nervos CKB Permit load cell data from memory
• VulnerabilityGHSA-29c2-65rj-h343 · 2024-02-03Nervos CKB Permit load cell data from memory
• VulnerabilityGHSA-29c2-65rj-h343 · 2024-02-03Nervos CKB Permit load cell data from memory
• VulnerabilityGHSA-3gjh-29fv-8hr6 · 2024-02-03Nervos CKB Snappy decompress length can be very large and causes out of memory error

Full security history of ckb