CVE-2020-18382Public exploitNetwork attack vector

Tool crash via out-of-bounds block read

Published Aug 22, 2023 · Updated Oct 7, 2024

Heap-buffer overflow in Binaryen 1.38.26 allows remote attackers to crash wasm-opt by supplying a crafted WebAssembly binary. The WasmBinaryBuilder::visitBlock function reads one byte beyond the end of its 150-byte input buffer while recursively parsing nested if and block expressions. Processing attacker-supplied WebAssembly is required, and the demonstrated consequence is termination of the invoked tool rather than code execution.

CVSS severity6.5
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-buffer overflow in Binaryen 1.38.26 allows remote attackers to crash wasm-opt by supplying a crafted WebAssembly binary. The WasmBinaryBuilder::visitBlock function reads one byte beyond the end of its 150-byte input buffer while recursively parsing nested if and block expressions. Processing attacker-supplied WebAssembly is required, and the demonstrated consequence is termination of the invoked tool rather than code execution.

The record

CVE
CVE-2020-18382
Published
Aug 22, 2023
Updated
Oct 7, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 7, 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

6.5NIST NVDCVSS:3.1/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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