CVE-2021-45947

Application crash via Runtime_Release out-of-bounds write

Published Dec 31, 2021 · Updated Aug 4, 2024

Out-of-bounds write in Wasm3 0.5.0 allows local users to crash an embedding application with a crafted WebAssembly module. Runtime_Release writes beyond an allocated memory region while EvaluateExpression processes data-segment initialization. Exploitation requires a local user to make an embedding application process the malformed module; published evidence demonstrates an availability-impacting crash, not code execution.

CVSS severity5.5
Medium
EPSS probability0.67%
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 write in Wasm3 0.5.0 allows local users to crash an embedding application with a crafted WebAssembly module. Runtime_Release writes beyond an allocated memory region while EvaluateExpression processes data-segment initialization. Exploitation requires a local user to make an embedding application process the malformed module; published evidence demonstrates an availability-impacting crash, not code execution.

The record

CVE
CVE-2021-45947
Published
Dec 31, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 31, 2021CVE 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

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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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