CVE-2021-46020Public exploitNetwork attack vector

Application crash via untrusted pointer dereference

Published Jan 14, 2022 · Updated Aug 4, 2024

Untrusted pointer dereference in mruby 3.0.0 allows attackers to crash an application by supplying a crafted Ruby program. mrb_vm_exec treats a crafted expression's invalid value as an object pointer and dereferences it during virtual-machine execution. Reachability depends on a host application executing attacker-controlled Ruby code; the demonstrated impact is a segmentation fault that terminates that process.

CVSS severity7.5
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Untrusted pointer dereference in mruby 3.0.0 allows attackers to crash an application by supplying a crafted Ruby program. mrb_vm_exec treats a crafted expression's invalid value as an object pointer and dereferences it during virtual-machine execution. Reachability depends on a host application executing attacker-controlled Ruby code; the demonstrated impact is a segmentation fault that terminates that process.

The record

CVE
CVE-2021-46020
Published
Jan 14, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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