What is CVE-2022-1212?

CVE-2022-1212 is a critical-severity vulnerability in Mruby, classified under Use After Free. CVSS score: 9.8/10. Published 2022-04-05.

How severe is CVE-2022-1212?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Use After Free in Mruby

CVE-2022-1212

Use-After-Free in str_escape in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary code execution if being exploited.

Vulnerability class: Use-After-Free

Published 2022-04-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.018 (77.6th percentile), scored 2026-10-03.

Low probability of exploitation in the next 30 days, but still tracked. 78th percentile — 77.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000

Affected products

Mruby — versions 3.1.0
Mruby Mruby/mruby — versions unspecified

Weakness classification (CWE)

CWE-416 — Use After Free

References

huntr.dev/bounties/9fcc06d0-08e4-49c8-afda-2cae40946abe (Exploit, Patch, Third Party Advisory, Issue Tracking)
github.com/mruby/mruby/commit/3cf291f72224715942beaf8553e42ba8891ab3c6 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2022-1212?: CVE-2022-1212 is a critical-severity vulnerability in Mruby, classified under Use After Free. CVSS score: 9.8/10. Published 2022-04-05.
How severe is CVE-2022-1212?: Critical severity. CVSS v3 base score is 9.8 out of 10.