What is CVE-2021-46020?

CVE-2021-46020 is a high-severity vulnerability in Mruby, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2022-01-14.

How severe is CVE-2021-46020?

High severity. CVSS v3 base score is 7.5 out of 10.

Buffer overflow in Mruby

CVE-2021-46020

An untrusted pointer dereference in mrb_vm_exec() of mruby v3.0.0 can lead to a segmentation fault or application crash.

Vulnerability class: Buffer Overflow

Published 2022-01-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (62.8th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 62.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Mruby — versions 3.0.0

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

github.com/mruby/mruby/issues/5613 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-46020?: CVE-2021-46020 is a high-severity vulnerability in Mruby, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2022-01-14.
How severe is CVE-2021-46020?: High severity. CVSS v3 base score is 7.5 out of 10.