CVE-2021-29328Public exploit

Memory disclosure and crash via debug buffer over-read

Published Nov 19, 2021 · Updated Aug 3, 2024

Out-of-bounds read in Moddable 10.5.0 allows local users to read process memory or crash the XS runtime through crafted JavaScript. A malformed property-access sequence reaches fxEnvironmentGetProperty, which raises an exception that fxDebugThrow handles by reading past the valid buffer boundary. Execution of the supplied script is required; the published proof of concept terminates xst with an AddressSanitizer-reported segmentation fault.

CVSS severity7.1
High
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Moddable 10.5.0 allows local users to read process memory or crash the XS runtime through crafted JavaScript. A malformed property-access sequence reaches fxEnvironmentGetProperty, which raises an exception that fxDebugThrow handles by reading past the valid buffer boundary. Execution of the supplied script is required; the published proof of concept terminates xst with an AddressSanitizer-reported segmentation fault.

The record

CVE
CVE-2021-29328
Published
Nov 19, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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

7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:N/A:P

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-125Out-of-bounds Read

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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