What’s Vulnerable › Vulnerabilities

CVE-2023-23557

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-05-18 · updated 2026-06-17
• Weakness: CWE-843

Description

An error in Hermes' algorithm for copying objects properties prior to commit a00d237346894c6067a594983be6634f4168c9ad could be used by a malicious attacker to execute arbitrary code via type confusion. Note that this is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.

Affected products

• Facebook Hermes: before 2023-01-10 — fixed in 2023-01-10

How to fix

Upgrade to a fixed version: Facebook Hermes 2023-01-10. Check the vendor advisory for mitigations.

References

• https://github.com/facebook/hermes/commit/a00d237346894c6067a594983be6634f4168c9ad
• https://www.facebook.com/security/advisories/cve-2023-23557
• https://github.com/facebook/hermes/commit/a00d237346894c6067a594983be6634f4168c9ad
• https://www.facebook.com/security/advisories/cve-2023-23557

Get alerted when CVE-2023-23557 or the next vulnerability affects your stack