---
id: CVE-2026-79590
title: >-
  A NULL pointer dereference vulnerability exists in the Prism parser component
  of mruby 4.0.0
summary: >-
  A NULL pointer dereference vulnerability exists in the Prism parser component
  of mruby 4.0.0. An attacker can provide a specially crafted Ruby source file
  that triggers the parser to pass a NULL pointer to nonnull string handling
  functio…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
published: '2026-09-10'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T20:00:03.713'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-79590'
references:
  - url: 'https://github.com/mruby/mruby/issues/7032'
    label: cve@mitre.org
  - url: >-
      https://github.com/takumin/mruby/commit/c6866eed4ad5640b552ba79d16063e7ec70a0ac9
    label: cve@mitre.org
  - url: 'https://github.com/mruby/mruby/issues/7032'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00367
epssPercentile: 0.27869
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-14T17:16:11.550926Z'
ingestedAt: '2026-09-11T16:45:48.021Z'
---

## Overview

A NULL pointer dereference vulnerability exists in the Prism parser component of mruby 4.0.0. An attacker can provide a specially crafted Ruby source file that triggers the parser to pass a NULL pointer to nonnull string handling functions, resulting in undefined behavior and application crash.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.