CVE-2022-31169

Cranelift vulnerable to miscompilation of constant values in division on AArch64

5.9 MediumFix available

Wasmtime is a standalone runtime for WebAssembly. There is a bug in Wasmtime's code generator, Cranelift, for AArch64 targets where constant divisors can result in incorrect division results at runtime. This affects Wasmtime prior to version 0.38.2 and Cranelift prior to 0.85.2. This issue only affects the AArch64 platform. Other platforms are not affected. The translation rules for constants did not take into account whether sign or zero-extension should happen which resulted in an incorrect value being placed into a register when a division was encountered. The impact of this bug is that programs executing within the WebAssembly sandbox would not behave according to the WebAssembly specification. This means that it is hypothetically possible for execution within the sandbox to go awry and WebAssembly programs could produce unexpected results. This should not impact hosts executing WebAssembly but does affect the correctness of guest programs. This bug has been patched in Wasmtime version 0.38.2 and cranelift-codegen 0.85.2. There are no known workarounds.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

0.92%Down 1.6 points since Jul 22, 2022

What each source reports

CVE List Score used 5.9

Cranelift vulnerable to miscompilation of constant values in division on AArch64

Record: CVE-2022-31169
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-682
Updated: 2026-11-02

EUVDEUVD-2022-6282 5.9

Record: EUVD-2022-6282
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-7f6x-jwh5-m9r4 5.9

Cranelift vulnerable to miscompilation of constant values in division on AArch64

Impact

There was a bug in Wasmtime's code generator, Cranelift, for AArch64 targets where constant divisors could result in incorrect division results at runtime. The translation rules for constants did not take into account whether sign- or zero-extension should happen, which resulted in an incorrect value being placed into a register when a division was encountered. For example, a constant 32-bit unsigned divisor of 0xfffffffe would be incorrectly sign-extended to 64-bits to 0xfffffffffffffffe. Any kind of division of operands smaller than 64 bits is implemented with a 64-bit division instruction which would then result in an incorrect result because the divisor was larger than expected.

The impact of this bug is that programs executing within the WebAssembly sandbox would not behave according to the WebAssembly specification. This means that it is hypothetically possible for execution within the sandbox to go awry and WebAssembly programs could produce unexpected results. This should not impact hosts executing WebAssembly, but does affect the correctness of guest programs.

This bug was found with differential fuzzing of Wasmtime against other engines on the AArch64 platform. Fuzzing on AArch64 is not regularly performed at this time and the Wasmtime team is investigating how best to continuously fuzz AArch64 in the same manner as x86_64.

Patches

This bug has been patched and users should upgrade to Wasmtime version 0.38.2.

Workarounds

If upgrading is not an option at this time, direct users of Cranelift that control the exact Cranelift instructions being compiled can avoid the vulnerability by explicitly extending constant divisors to 64 bits using either the sextend.i64 or the uextend.i64 operation.

Note, though, that this issue only affects the AArch64 targets. Other platforms are not affected.

For more information

If you have any questions or comments about this advisory:

Reach out to us on the Bytecode Alliance Zulip chat
Open an issue in the bytecodealliance/wasmtime repository

Record: GHSA-7f6x-jwh5-m9r4
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-682
Updated: 2026-11-02

NVD 5.9

Record: CVE-2022-31169
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-682
Updated: 2026-11-02

OSVCVE-2022-23636 5.1

Invalid drop of partially-initialized instances in wasmtime

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.

Record: CVE-2022-23636
CVSS 3.1: 5.1 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-824
Updated: 2026-11-02

OSV 5.9

Cranelift vulnerable to miscompilation of constant values in division on AArch64

Record: CVE-2022-31169
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-682
Updated: 2026-11-02

Show 5 moreShow less

OSVGHSA-7f6x-jwh5-m9r4 5.9

Cranelift vulnerable to miscompilation of constant values in division on AArch64

Impact

Patches

This bug has been patched and users should upgrade to Wasmtime version 0.38.2.

Workarounds

Note, though, that this issue only affects the AArch64 targets. Other platforms are not affected.

For more information

If you have any questions or comments about this advisory:

Reach out to us on the Bytecode Alliance Zulip chat
Open an issue in the bytecodealliance/wasmtime repository

Record: GHSA-7f6x-jwh5-m9r4
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-682
Updated: 2026-11-02

OSVGHSA-88xq-w8cq-xfg7 5.1

Invalid drop of partially-initialized instances in the pooling instance allocator for modules with defined `externref` globals

Impact

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.

As instance slots may be reused between consecutive instantiations, the value of the uninitialized pointer may be from a previous instantiation and therefore under the control of an attacker via a module's initial values for its globals. If the attacker can somehow determine an address under their control inside the mapped memory representing the instance pool, it is possible to trick the runtime to call drop_in_place on a trait object under the attacker's control and therefore cause remote code execution.

Exploiting the bug to cause remote code execution would be very difficult as attackers cannot determine the addresses of globals from code executing within the WebAssembly VM and the memory space for the instance pool cannot be statically determined. Operating system mitigations, such as address space layout randomization, would additionally increase the difficulty for attackers to determine useful executable code to target with an exploit. It is also very unlikely that attackers will be able to directly influence the conditions that trigger the bug as described below.

When the conditions to trigger the bug are met, however, it is much easier to exploit this bug to cause a denial of service by crashing the host with an invalid memory read.

The following engine configuration (via Config) is required to be impacted by this bug:

support for the reference types proposal must be enabled (this is the default for Config).
a pooling allocation strategy must be configured via Config::allocation_strategy, which is not the default allocation strategy.

A module must be instantiated with all the following characteristics:

The module defines at least one table or memory.
The module defines at least one externref global.

During instantiation, one of the following must occur to cause the instantiation to fail:

a call to mprotect or VirtualAlloc fails (e.g. out-of-memory conditions).
a resource limiter was configured in the associated Store (via Store::limiter or Store::limiter_async) and the limiter returns false from the initial call to memory_growing or table_growing. Stores do not have a resource limiter set by default.

This results in a partially-initialized instance being dropped and that attempts to drop the uninitialized VMExternRef representing the defined externref global.

We have reason to 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; if no resource limiter is used, then this configuration is not vulnerable.

Patches

The bug has been fixed in 0.34.1 and 0.33.1; users are encouraged to upgrade as soon as possible.

Workarounds

If it is not possible to upgrade to 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…

Record: GHSA-88xq-w8cq-xfg7
CVSS 3.1: 5.1 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-824
Updated: 2026-11-02

OSVUBUNTU-CVE-2022-31169 7.5

Record: UBUNTU-CVE-2022-31169
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 3.1: 5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVRUSTSEC-2022-0096 No score

Invalid drop of VMExternRef from partially-initialized instances in the pooling instance allocator

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-88xq-w8cq-xfg7. For more information see the GitHub-hosted security advisory.

Record: RUSTSEC-2022-0096
Updated: 2026-11-02

OSVRUSTSEC-2022-0101 No score

Miscompilation of constant values in division on AArch64

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-7f6x-jwh5-m9r4. For more information see the GitHub-hosted security advisory.

Record: RUSTSEC-2022-0101
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`wasmtime` crates.io	before 0.38.2	0.38.2
`cranelift-codegen` crates.io	before 0.85.2	0.85.2
`wasmtime` crates.io From an advisory covering 2 CVEs	before 0.38.2	0.38.2
`cranelift-codegen` crates.io From an advisory covering 2 CVEs	before 0.85.2	0.85.2
`wasmtime` crates.io From an advisory covering 2 CVEs	0.34.0 up to 0.34.1	0.34.1
`wasmtime` crates.io From an advisory covering 2 CVEs	before 0.33.1	0.33.1
`wasmtime` crates.io From an advisory covering 2 CVEs	0.0.0-0 up to 0.33.1, 0.34.0 up to 0.34.1	0.33.10.34.1
`wasmtime` crates.io From an advisory covering 2 CVEs	0.0.0-0 up to 0.38.2	0.38.2
`mozjs52` Ubuntu:18.04:LTS	All versions, plus listed versions 52.3.1-0ubuntu352.3.1-7fakesync152.8.1-0ubuntu0.18.04.152.9.1-0ubuntu0.18.04.1	None known
`mozjs38` Ubuntu:18.04:LTS	All versions, plus listed versions 38.8.0~repack1-0ubuntu138.8.0~repack1-0ubuntu338.8.0~repack1-0ubuntu4	None known

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Affected packages
Package	Affected	Fixed
`mozjs68` Ubuntu:20.04:LTS	All versions, plus listed versions 68.5.0-1~fakesync68.5.0-2~fakesync68.6.0-168.6.0-1ubuntu1	None known
`mozjs52` Ubuntu:20.04:LTS	All versions, plus listed versions 52.9.1-1build152.9.1-1ubuntu3	None known
`mozjs78` Ubuntu:22.04:LTS	All versions, plus listed versions 78.13.0-178.15.0-278.15.0-4ubuntu1	None known
`mozjs91` Ubuntu:22.04:LTS	All versions, plus listed versions 91.5.1-0ubuntu191.6.0-191.6.0-291.7.0-291.10.0-0ubuntu1	None known
`thunderbird` Ubuntu:22.04:LTS	All versions, plus listed versions 1:91.1.2+build1-0ubuntu11:91.3.0+build2-0ubuntu11:91.3.1+build1-0ubuntu11:91.3.2+build1-0ubuntu11:91.4.0+build1.1-0ubuntu1 Show 34 moreShow less 1:91.4.0+build2-0ubuntu11:91.5.0+build1-0ubuntu11:91.5.1+build1-0ubuntu11:91.6.1+build1-0ubuntu11:91.7.0+build1-0ubuntu11:91.7.0+build2-0ubuntu11:91.8.0+build2-0ubuntu11:91.9.1+build1-0ubuntu0.22.04.11:91.11.0+build2-0ubuntu0.22.04.11:102.2.2+build1-0ubuntu0.22.04.11:102.4.2+build2-0ubuntu0.22.04.11:102.7.1+build2-0ubuntu0.22.04.11:102.8.0+build2-0ubuntu0.22.04.11:102.9.0+build1-0ubuntu0.22.04.11:102.10.0+build2-0ubuntu0.22.04.11:102.11.0+build1-0ubuntu0.22.04.11:102.13.0+build1-0ubuntu0.22.04.11:102.15.0+build1-0ubuntu0.22.04.11:102.15.1+build1-0ubuntu0.22.04.11:115.3.1+build1-0ubuntu0.22.04.21:115.4.1+build1-0ubuntu0.22.04.11:115.5.0+build1-0ubuntu0.22.04.11:115.6.0+build2-0ubuntu0.22.04.11:115.8.1+build1-0ubuntu0.22.04.11:115.9.0+build1-0ubuntu0.22.04.11:115.10.1+build1-0ubuntu0.22.04.11:115.11.0+build2-0ubuntu0.22.04.11:115.12.0+build3-0ubuntu0.22.04.11:115.13.0+build5-0ubuntu0.22.04.11:115.15.0+build1-0ubuntu0.22.04.11:115.16.0+build2-0ubuntu0.22.04.11:115.18.0+build1-0ubuntu0.22.04.11:128.12.0+build1-0ubuntu0.22.04.11:140.7.1+build1-0ubuntu0.22.04.1	None known
`thunderbird` Ubuntu:24.04:LTS	All versions, plus listed versions 1:115.3.1+build1-0ubuntu11:115.4.1+build1-0ubuntu11:115.4.3+build1-0ubuntu11:115.5.0+build1-0ubuntu11:115.5.1+build1-0ubuntu1 Show 9 moreShow less 1:115.5.2+build2-0ubuntu11:115.6.0+build1-0ubuntu11:115.6.0+build2-0ubuntu11:115.6.1+build1-0ubuntu11:115.8.0+build1-0ubuntu11:115.8.1+build1+snap21:115.8.1+build1+snap32:1snap1-0ubuntu12:1snap1-0ubuntu3	None known

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2022-31169 is a medium vulnerability (CVSS 5.9) in Bytecodealliance Cranelift-codegen, published February 16, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. Fixed in wasmtime 0.38.2.

References

Show 9 moreShow less

This page doesn't list everything

Left out here: the rest of 1 source description. The JSON record has them.