{"cve":"CVE-2021-38196","nvd":{"published":"2021-08-08T06:15:09.153","modified":"2026-06-17T04:01:44.367","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-94"],"references":["https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.md","https://rustsec.org/advisories/RUSTSEC-2021-0077.html","https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.md","https://rustsec.org/advisories/RUSTSEC-2021-0077.html"],"products":["better-macro_project:better-macro"],"source":"nvd","synced_at":"2026-10-19T21:21:13.713336758+00:00"},"epss":{"cve":"CVE-2021-38196","score":0.02567,"percentile":0.85136,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-79wf-qcqv-r22r","url":"https://osv.dev/vulnerability/GHSA-79wf-qcqv-r22r","summary":"Remote code execution in better-macro","modified":"2023-11-08T04:06:26.288170Z","packages":[{"ecosystem":"crates.io","name":"better-macro","purl":"pkg:cargo/better-macro","ranges":["<=1.0.4"],"fixed":[]}]},{"id":"RUSTSEC-2021-0077","url":"https://osv.dev/vulnerability/RUSTSEC-2021-0077","summary":"`better-macro` has deliberate RCE to prove a point","modified":"2023-11-08T04:06:26.288170Z","packages":[{"ecosystem":"crates.io","name":"better-macro","purl":"pkg:cargo/better-macro","ranges":[">=0.0.0-0"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}