CVE-2022-1212Network attack vector

Code execution via premature GC arena restoration

Published Apr 5, 2022 · Updated Aug 2, 2024

Use-after-free in mruby before 3.2 allows attackers to execute arbitrary code through a crafted Ruby program that reaches str_escape. In mrb_vm_exec, the VM restored the garbage-collector arena before creating the break exception object, allowing live references to be reclaimed and later dereferenced during string escaping. Exploitation requires untrusted Ruby input to reach this exception path; a successful trigger can compromise or crash the embedding process.

CVSS severity9.8
Critical
EPSS probability1.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in mruby before 3.2 allows attackers to execute arbitrary code through a crafted Ruby program that reaches str_escape. In mrb_vm_exec, the VM restored the garbage-collector arena before creating the break exception object, allowing live references to be reclaimed and later dereferenced during string escaping. Exploitation requires untrusted Ruby input to reach this exception path; a successful trigger can compromise or crash the embedding process.

The record

CVE
CVE-2022-1212
Published
Apr 5, 2022
Updated
Aug 2, 2024
Vendor
mruby
Product
mruby
Classifications
CWE-416
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=unspecified <3.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

mruby · mrubyversion=unspecified <3.2

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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