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WasmtimeApplication · Bytecodealliance

CVE-2023-41880

MEDIUM · 5.3 CVSS v3.1 Published 2023-09-15
Fix available
A fix is available. Upgrade to 10.0.2 / 11.0.2 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Wasmtime is a standalone runtime for WebAssembly. Wasmtime versions from 10.0.0 to versions 10.02, 11.0.2, and 12.0.1 contain a miscompilation of the WebAssembly `i64x2.shr_s` instruction on x86_64 platforms when the shift amount is a constant value that is larger than 32. Only x86_64 is affected so all other targets are not affected by this. The miscompilation results in the instruction producing an incorrect result, namely the low 32-bits of the second lane of the vector are derived from the low 32-bits of the second lane of the input vector instead of the high 32-bits. The primary impact of this issue is that any WebAssembly program using the `i64x2.shr_s` with a constant shift amount larger than 32 may produce an incorrect result. This issue is not an escape from the WebAssembly sandbox. Execution of WebAssembly guest programs will still behave correctly with respect to memory sandboxing and isolation from the host. Wasmtime considers non-spec-compliant behavior as a security issue nonetheless. This issue was discovered through fuzzing of Wasmtime's code generator Cranelift. Wasmtime versions 10.0.2, 11.0.2, and 12.0.2 are all patched to no longer have this miscompilation. This issue only affects x86_64 hosts and the only workaround is to either scan for this pattern in wasm modules which is nontrivial or to disable the SIMD proposal for WebAssembly. Users prior to 10.0.0 are unaffected by this vulnerability.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
WasmtimeApplication
Affected:>= 10.0.0, < 10.0.2>= 11.0.0, < 11.0.2>= 12.0.0, < 12.0.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.2 / 11.0.2 / 12.0.2 or later
Fixed in 10.0.211.0.212.0.2
Vendor patch github.com →
Recommended fix High confidence

Wasmtime 10.0.2, 11.0.2, or 12.0.2 (matching your current major version line)

  1. 1. Identify the current Wasmtime version in use (e.g., via cargo.toml, Cargo.lock, or runtime version check)
  2. 2. Determine which major version line you are on: 10.x, 11.x, or 12.x
  3. 3. Upgrade to the corresponding fixed release: Wasmtime 10.0.2 for 10.x users, 11.0.2 for 11.x users, or 12.0.2 for 12.x users
  4. 4. Update the dependency in your project (e.g., cargo update -p wasmtime or update your Cargo.lock)
  5. 5. Rebuild and redeploy your application with the patched Wasmtime version
  6. 6. Test WebAssembly workloads that use i64x2.shr_s SIMD instructions to verify correct behavior
  7. 7. Deploy the updated version to production
Caveat Review the Wasmtime release notes for 10.0.2, 11.0.2, and 12.0.2 for any breaking changes between your current version and the target patched version

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-41880 in production — separate from our analysis above.

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