CVE-2023-41880

What it is

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.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. Limited direct impact.

Exploit odds

0.7% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-09-15 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:22 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.7% in the next 30 days (EPSS).
• Severity: 2.2 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-09-15 20:15 UTC

Last modified

2026-06-17 06:22 UTC

Exploit probability

0.7% · EPSS, next 30 days

Weakness

CWE-193

Record status

Modified

Affected

• Bytecodealliance Wasmtime < 10.0.2
• Bytecodealliance Wasmtime < 11.0.2
• Bytecodealliance Wasmtime < 12.0.2

Attack profile CVSS 3.1 · 2.2

Attack vector

Network

Complexity

High

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-41880.md and follow it. Check whether this project is affected by CVE-2023-41880. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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