Vulnerability · Published Jun 15, 2021 · Assigned by facebook

CVE-2021-24037

Critical 9.8

In plain English

A critical-severity use-after-free in Hermes from Facebook. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.8% (higher than 79% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)9.8Critical

Exploit odds (30 days)1.8%top 21.5% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	hermes-engine	0.8.0	GHSA-mph8-6787-r8hw

Affected products (as reported)

Vendor	Product	Versions
Facebook	Hermes	commit prior to d86e185e485b6330216dee8e854455c694e3a36e

Weakness: CWE-416

References

https://github.com/facebook/hermes/commit/d86e185e485b6330216dee8e854455c694e3a36e x_refsource_CONFIRM
https://www.facebook.com/security/advisories/CVE-2021-24037 x_refsource_CONFIRM