A use-after-free related to unsound inference in the bytecode generation when optimizations are enabled for Hermes prior to commit da8990f737ebb9d9810633502f65ed462b819c09 could have been used by an attacker to achieve remote code execution. Note that this is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Hermes | - (including) | - (including) |