CVE-2022-0481Public exploit

Compiler crash via discarded hash expression

Published Feb 4, 2022 · Updated Aug 2, 2024

NULL pointer dereference in mruby before 3.2 allows local users to crash its compiler by processing a crafted Ruby hash expression. In gen_hash in mrbgems/mruby-compiler/core/codegen.c, discarded-value hash generation pops stack entries and emits OP_HASHCAT even when val is false. Exploitation requires a user to compile or execute attacker-controlled Ruby source, and the reported consequence is termination of that process.

CVSS severity5.5
Medium
EPSS probability0.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in mruby before 3.2 allows local users to crash its compiler by processing a crafted Ruby hash expression. In gen_hash in mrbgems/mruby-compiler/core/codegen.c, discarded-value hash generation pops stack entries and emits OP_HASHCAT even when val is false. Exploitation requires a user to compile or execute attacker-controlled Ruby source, and the reported consequence is termination of that process.

The record

CVE
CVE-2022-0481
Published
Feb 4, 2022
Updated
Aug 2, 2024
Vendor
mruby
Product
mruby
Classifications
CWE-476
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

mruby · mrubyversion=unspecified <3.2

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5Protect AI (formerly huntr.dev)CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference

Public exploit references

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Technologies

Your stack

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Your stack

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