What’s Vulnerable › Vulnerabilities

CVE-2021-4188: NULL Pointer Dereference in mruby/mruby

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-30 · updated 2026-06-17
• Weakness: CWE-476

Description

mruby is vulnerable to NULL Pointer Dereference

Affected products

• mruby/mruby: through 3.0.0

References

• https://github.com/mruby/mruby/commit/27d1e0132a0804581dca28df042e7047fd27eaa8
• https://huntr.dev/bounties/78533fb9-f3e0-47c2-86dc-d1f96d5bea28
• https://github.com/mruby/mruby/commit/27d1e0132a0804581dca28df042e7047fd27eaa8
• https://huntr.dev/bounties/78533fb9-f3e0-47c2-86dc-d1f96d5bea28

Get alerted when CVE-2021-4188 or the next vulnerability affects your stack