CVE-2022-39394

Out-of-bounds write via C API signature mismatch

Published Nov 10, 2022 · Updated Apr 23, 2025

Out-of-bounds write in Wasmtime before 2.0.2 allows attackers to corrupt adjacent memory via the C API wasmtime_trap_code function. Its implementation writes four bytes although the header declares a one-byte output buffer, placing three zero bytes beyond the caller's allocation. Exploitation requires code that invokes this C API with the undersized buffer; the Rust wasmtime crate API is unaffected, while memory corruption can crash or destabilize the embedding process.

CVSS severity9.8
Critical
EPSS probability0.34%
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 Wasmtime before 2.0.2 allows attackers to corrupt adjacent memory via the C API wasmtime_trap_code function. Its implementation writes four bytes although the header declares a one-byte output buffer, placing three zero bytes beyond the caller's allocation. Exploitation requires code that invokes this C API with the undersized buffer; the Rust wasmtime crate API is unaffected, while memory corruption can crash or destabilize the embedding process.

The record

CVE
CVE-2022-39394
Published
Nov 10, 2022
Updated
Apr 23, 2025
Vendor
Bytecode Alliance
Product
Wasmtime
Classifications
CWE-787, T1203
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 10, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.0.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Bytecode Alliance · Wasmtimeversion=< 2.0.2

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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