Wasmtime out of bounds read/write with zero-memory-pages configuration

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N

EPSS

• CVE-2022-39392: 0.66% estimated exploitation activity in the next 30 days; percentile 51.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact There is a bug in Wasmtime's implementation of its pooling instance allocator when the allocator is configured to give WebAssembly instances a maximum of zero pages of memory. In this configuration the virtual memory mapping for WebAssembly memories did not meet the compiler-required configuration requirements for safely executing WebAssembly modules. Wasmtime's default settings require virtual memory page faults to indicate that wasm reads/writes are out-of-bounds, but the pooling allocator's configuration would not create an appropriate virtual memory mapping for this meaning out of bounds reads/writes can successfully read/write memory unrelated to the wasm sandbox within range of the base address of the memory mapping created by the pooling allocator. This bug can only be triggered by setting InstanceLimits::memorypages to zero. This is expected to be a very rare configuration since this means that wasm modules cannot allocate any pages of linear memory. All wasm modules…

Published by the source

10 Nov 2022, 21:09 UTC

Last modified by the source

2 May 2025, 12:49 UTC

Source last checked

26 Oct 2026, 15:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-44mr-8vmm-wjhg

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# Patch Next advisory brief: CVE-2022-39392

Advisory: Wasmtime out of bounds read/write with zero-memory-pages configuration
IDs: CVE-2022-39392, GHSA-44mr-8vmm-wjhg
Record: https://patchnext.com/advisories/cve-2022-39392 (revision 1, source checked 26 Oct 2026, 15:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: wasmtime 2.0.2, 1.0.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io wasmtime: affected >= 2.0.0, < 2.0.2; < 1.0.2; fixed in 1.0.2, 2.0.2

## Suggested inspection (read-only)
- crates.io wasmtime: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wasmtime.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-44mr-8vmm-wjhg (GitHub-reviewed advisory GHSA-44mr-8vmm-wjhg lists affected ranges: crates.io wasmtime >=2.0.0 =0 <1.0.2)

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