Memory access due to code generation flaw in Cranelift module

Exploitation

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

CVSS

7.2 · CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2021-32629: 0.46% estimated exploitation activity in the next 30 days; percentile 39.51 (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.

There is a bug in 0.73.0 of the Cranelift x64 backend that can create a scenario that could result in a potential sandbox escape in a WebAssembly module. Users of versions 0.73.0 of Cranelift should upgrade to either 0.73.1 or 0.74 to remediate this vulnerability. Users of Cranelift prior to 0.73.0 should update to 0.73.1 or 0.74 if they were not using the old default backend. Description This bug was introduced in the new backend on 2020-09-08 and first included in a release on 2020-09-30, but the new backend was not the default prior to 0.73.0. The recently-released version 0.73.0 with default settings, and prior versions with an explicit build flag to select the new backend, are vulnerable. The bug in question performs a sign-extend instead of a zero-extend on a value loaded from the stack, under a specific set of circumstances. If those circumstances occur, the bug could allow access to memory addresses up to 2GiB before the start of the heap allocated for the WebAssembly module.…

Published by the source

25 Aug 2021, 21:01 UTC

Last modified by the source

8 Jul 2026, 06:30 UTC

Source last checked

26 Oct 2026, 13:27 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hpqh-2wqx-7qp5

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hpqh-2wqx-7qp5

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# Patch Next advisory brief: CVE-2021-32629

Advisory: Memory access due to code generation flaw in Cranelift module
IDs: CVE-2021-32629, GHSA-hpqh-2wqx-7qp5
Record: https://patchnext.com/advisories/cve-2021-32629 (revision 2, source checked 26 Oct 2026, 13:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: wasmtime 0.27.0; cranelift-codegen 0.73.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI wasmtime: affected < 0.27.0; fixed in 0.27.0
- crates.io cranelift-codegen: affected < 0.73.1; fixed in 0.73.1

## Suggested inspection (read-only)
- `python -m pip show wasmtime`: prints the installed version. Run with the environment that serves production active.
- crates.io cranelift-codegen: 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, cranelift-codegen.
- 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://osv.dev/vulnerability/GHSA-hpqh-2wqx-7qp5 (OSV record GHSA-hpqh-2wqx-7qp5 lists affected ranges: crates.io cranelift-codegen >=0 =0 <0.27.0 (fixed))
- Verified: https://github.com/advisories/GHSA-hpqh-2wqx-7qp5 (GitHub-reviewed advisory GHSA-hpqh-2wqx-7qp5 lists affected ranges: crates.io cranelift-codegen >=0 =0 <0.27.0)

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