CVE-2021-38196

Name: CVE-2021-38196
Creator: NVD / NIST
Published: 2021-08-08T06:15:09.153+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.57%

Last modified Jun 17, 2026

CVE-2021-38196 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 2.57% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.57%

83.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-94

Affected Software

Vendor	Product	Versions
Better-Macro Project	Better-Macro	<= 2021-07-22

References

https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.mdThird Party Advisory
https://rustsec.org/advisories/RUSTSEC-2021-0077.htmlExploit, Issue Tracking, Patch, Third Party Advisory
https://raw.githubusercontent.com/rustsec/advisory-db/main/crates/better-macro/RUSTSEC-2021-0077.mdThird Party Advisory
https://rustsec.org/advisories/RUSTSEC-2021-0077.htmlExploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Aug 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-38196?

How severe is CVE-2021-38196?

CVE-2021-38196 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.57% probability of exploitation in the next 30 days.

How do I fix CVE-2021-38196?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-38196?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST