CVE-2021-24037

Name: CVE-2021-24037
Creator: NVD / NIST
Published: 2021-06-15T22:15:08.68+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.80%

Last modified Jun 17, 2026

CVE-2021-24037 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A use after free in hermes, while emitting certain error messages, prior to commit d86e185e485b6330216dee8e854455c694e3a36e allows attackers to potentially execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. EPSS estimates a 1.80% chance of exploitation in the next 30 days.

Description

A use after free in hermes, while emitting certain error messages, prior to commit d86e185e485b6330216dee8e854455c694e3a36e allows attackers to potentially execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.

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

1.80%

75.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Facebook	Hermes	< 0.8.0

References

https://github.com/facebook/hermes/commit/d86e185e485b6330216dee8e854455c694e3a36ePatch, Third Party Advisory
https://www.facebook.com/security/advisories/CVE-2021-24037Vendor Advisory
https://github.com/facebook/hermes/commit/d86e185e485b6330216dee8e854455c694e3a36ePatch, Third Party Advisory
https://www.facebook.com/security/advisories/CVE-2021-24037Vendor Advisory

Timeline

Published: Jun 15, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-24037?

How severe is CVE-2021-24037?

CVE-2021-24037 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.80% probability of exploitation in the next 30 days.

How do I fix CVE-2021-24037?

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-2021-24037?

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

Scan your code now

Source: NVD / NIST