CVE-2022-31169 is a medium-severity (CVSS 5.9) CWE-682 vulnerability in wasmtime. A fix is available for wasmtime — see the affected versions and patch details below.
Cranelift vulnerable to miscompilation of constant values in division on AArch64
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-31169.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-31169 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
wasmtime🦀cranelift-codegenReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | wasmtime | all versions | 0.38.2cargo update -p wasmtime --precise 0.38.2 |
| 🦀crates.io | cranelift-codegen | all versions | 0.85.2cargo update -p cranelift-codegen --precise 0.85.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wasmtime, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update wasmtime to 0.38.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-31169 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-31169 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-31169. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-31169 in your dependencies?
O3 Security finds CVE-2022-31169 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.