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Public proof of conceptFix available

CVE-2022-23636

A public proof of concept exists; no exploitation attested.

  • Published2022-02-16
  • Fixed in0.38.2 · 0.34.1 · 0.33.1
  • WeaknessCWE-824

Am I affected?

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Description

Wasmtime is an open source runtime for WebAssembly & WASI. Prior to versions 0.34.1 and 0.33.1, there exists a bug in the pooling instance allocator in Wasmtime's runtime where a failure to instantiate an instance for a module that defines an `externref` global will result in an invalid drop of a `VMExternRef` via an uninitialized pointer. A number of conditions listed in the GitHub Security Advisory must be true in order for an instance to be vulnerable to this issue. Maintainers believe that the effective impact of this bug is relatively small because the usage of `externref` is still uncommon and without a resource limiter configured on the `Store`, which is not the default configuration, it is only possible to trigger the bug from an error returned by `mprotect` or `VirtualAlloc`. Note that on Linux with the `uffd` feature enabled, it is only possible to trigger the bug from a resource limiter as the call to `mprotect` is skipped. The bug has been fixed in 0.34.1 and 0.33.1 and users are encouraged to upgrade as soon as possible. If it is not possible to upgrade to version 0.34.1 or 0.33.1 of the `wasmtime` crate, it is recommend that support for the reference types proposal be disabled by passing `false` to `Config::wasm_reference_types`. Doing so will prevent modules that use `externref` from being loaded entirely.

Timeline

dates in UTC
  1. 2022-02-1622:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2022-23636?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2022-23636?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV · NVD
Bytecodealliance wasmtime
BranchAffectedFixed in
0.x≥ 0.0.0-0, < 0.38.20.38.2
0.38< 0.38.20.38.2
0.34≥ 0.34.0, < 0.34.10.34.1
0.33< 0.33.10.33.1
0.x≥ 0.0.0-0, < 0.33.10.33.1
0.34= 0.34.0no fix published
cranelift-codegen
BranchAffectedFixed in
0.85< 0.85.20.85.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Bytecodealliance wasmtime to 0.38.2 · 0.34.1 · 0.33.1

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedcyhe50/cve-2022-23636-poc
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2025-04-23
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.15.1read 2026-10-23
  • NVDCVSS 3.18.1read 2026-10-23
  • NVDCVSS 2.07.1read 2026-10-23
  • CNAweakness (CWE)CWE-824read 2026-10-23
  • FIRST EPSSEPSS score0.8 %2026-10-23
  • PoC-in-GitHubproof of concept1read 2026-10-23
  • OSVaffected packages—

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2022-02-16
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2022-23636?

Wasmtime is an open source runtime for WebAssembly & WASI. Prior to versions 0.34.1 and 0.33.1, there exists a bug in the pooling instance allocator in Wasmtime's runtime where a failure to instantiate an instance for a module that defines an `externref` global will result in an invalid drop of a `VMExternRef` via an uninitialized pointer. A number of conditions listed in the GitHub Security Advisory must be true in order for an instance to be vulnerable to this issue. Maintainers believe that the effective impact of this bug is relatively small because the usage of `externref` is still uncommon and without a resource limiter configured on the `Store`, which is not the default configuration, it is only possible to trigger the bug from an error returned by `mprotect` or `VirtualAlloc`. Note that on Linux with the `uffd` feature enabled, it is only possible to trigger the bug from a resource limiter as the call to `mprotect` is skipped. The bug has been fixed in 0.34.1 and 0.33.1 and users are encouraged to upgrade as soon as possible. If it is not possible to upgrade to version 0.34.1 or 0.33.1 of the `wasmtime` crate, it is recommend that support for the reference types proposal be disabled by passing `false` to `Config::wasm_reference_types`. Doing so will prevent modules that use `externref` from being loaded entirely.

Is CVE-2022-23636 actively exploited?

Active exploitation of CVE-2022-23636 has not been confirmed. Its EPSS score was 0.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2022-23636?

CVE-2022-23636 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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