CVE-2021-38592Network attack vector

Process crash via untracked Const64 stack slot

Published Aug 12, 2021 · Updated Aug 4, 2024

Heap buffer overflow in Wasm3 0.5.0 allows attackers to crash an embedding process by loading a crafted WebAssembly module. During module initialization, EvaluateExpression compiles a Const64 instruction, but TouchSlot fails to update maxStackSlots outside a function, so op_Const64 writes eight bytes beyond the allocated stack. The host must load attacker-supplied WebAssembly; the demonstrated consequence is heap corruption and a process crash, not confirmed code execution.

CVSS severity7.5
High
EPSS probability1.29%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in Wasm3 0.5.0 allows attackers to crash an embedding process by loading a crafted WebAssembly module. During module initialization, EvaluateExpression compiles a Const64 instruction, but TouchSlot fails to update maxStackSlots outside a function, so op_Const64 writes eight bytes beyond the allocated stack. The host must load attacker-supplied WebAssembly; the demonstrated consequence is heap corruption and a process crash, not confirmed code execution.

The record

CVE
CVE-2021-38592
Published
Aug 12, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 12, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

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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