CVE-2021-46333Public exploit

Local denial of service via negative-size memmove

Published Jan 20, 2022 · Updated Aug 4, 2024

Moddable SDK 11.5.0 contains an invalid memory access flaw in __asan_memmove that allows local users to crash the interpreter via crafted JavaScript. The affected memory-management path passes a negative size to memmove while compiling repeatedly generated regular expressions, triggering an AddressSanitizer abort or segmentation fault. Exploitation requires execution of attacker-controlled script on the host; observed impact is service interruption without confidentiality or integrity loss.

CVSS severity5.5
Medium
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Moddable SDK 11.5.0 contains an invalid memory access flaw in __asan_memmove that allows local users to crash the interpreter via crafted JavaScript. The affected memory-management path passes a negative size to memmove while compiling repeatedly generated regular expressions, triggering an AddressSanitizer abort or segmentation fault. Exploitation requires execution of attacker-controlled script on the host; observed impact is service interruption without confidentiality or integrity loss.

The record

CVE
CVE-2021-46333
Published
Jan 20, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-119, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 20, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3[email protected]AV:N/AC:M/Au:N/C:N/I:N/A:P
5.5[email protected]CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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
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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