CVE-2021-44647Public exploit

Local interpreter crash via corrupted call frame

Published Jan 11, 2022 · Updated Aug 4, 2024

Type confusion in Lua 5.4.3 allows local users to crash the interpreter through error handling in a crafted script. During traceback construction, funcnamefromcode treats an overwritten previous call-frame value as a Lua function and dereferences it. The trigger requires a variadic function that calls os.exit and an error from a to-be-closed value's __close handler, terminating the interpreter process.

CVSS severity5.5
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Lua 5.4.3 allows local users to crash the interpreter through error handling in a crafted script. During traceback construction, funcnamefromcode treats an overwritten previous call-frame value as a Lua function and dereferences it. The trigger requires a variadic function that calls os.exit and an error from a to-be-closed value's __close handler, terminating the interpreter process.

The record

CVE
CVE-2021-44647
Published
Jan 11, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-843, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 11, 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 vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
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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