An integer conversion error in Hermes bytecode generation, prior to commit 6aa825e480d48127b480b08d13adf70033237097, could have been used to perform Out-Of-Bounds operations and subsequently execute arbitrary code. Note that this is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.

References

• https://nvd.nist.gov/vuln/detail/CVE-2022-40138
• facebook/hermes@6aa825e
• https://www.facebook.com/security/advisories/CVE-2022-40138