How severe is CVE-2023-27477?

CVE-2023-27477 has a CVSS 3.x base score of 3.1, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2023-27477 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-27477?

CVE-2023-27477 primarily affects Bytecodealliance Cranelift-codegen. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-27477?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-27477 published?

CVE-2023-27477 was published on 2023-03-08 and last updated on 2026-06-17.

CVE-2023-27477

CVE-2023-27477 is a low-severity vulnerability in Bytecodealliance Cranelift-codegen with a CVSS 3.x base score of 3.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-193.

Key facts

Severity: Low (CVSS 3.x base score 3.1)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-193
Affected product: Bytecodealliance Cranelift-codegen
Published: 2023-03-08
Last modified: 2026-06-17

Description

wasmtime is a fast and secure runtime for WebAssembly. Wasmtime's code generation backend, Cranelift, has a bug on x86_64 platforms for the WebAssembly `i8x16.select` instruction which will produce the wrong results when the same operand is provided to the instruction and some of the selected indices are greater than 16. There is an off-by-one error in the calculation of the mask to the `pshufb` instruction which causes incorrect results to be returned if lanes are selected from the second vector. This codegen bug has been fixed in Wasmtiem 6.0.1, 5.0.1, and 4.0.1. Users are recommended to upgrade to these updated versions. If upgrading is not an option for you at this time, you can avoid this miscompilation by disabling the Wasm simd proposal. Additionally the bug is only present on x86_64 hosts. Other platforms such as AArch64 and s390x are not affected.

Frequently asked questions

What is CVE-2023-27477?: wasmtime is a fast and secure runtime for WebAssembly. Wasmtime's code generation backend, Cranelift, has a bug on x86_64 platforms for the WebAssembly `i8x16.select` instruction which will produce the wrong results when the same operand is provided to the instruction and some of the selected indices are greater than 16. There is an off-by-one error in the calculation of the mask to the `pshufb` instruction which causes incorrect results to be returned if lanes are selected from the second vector. This codegen bug has been fixed in Wasmtiem 6.0.1, 5.0.1, and 4.0.1. Users are recommended to upgrade to these updated versions. If upgrading is not an option for you at this time, you can avoid this miscompilation by disabling the Wasm simd proposal. Additionally the bug is only present on x86_64 hosts. Other platforms such as AArch64 and s390x are not affected.
How severe is CVE-2023-27477?: CVE-2023-27477 has a CVSS 3.x base score of 3.1, rated low severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2023-27477 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-27477?: CVE-2023-27477 primarily affects Bytecodealliance Cranelift-codegen. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-27477?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-27477 published?: CVE-2023-27477 was published on 2023-03-08 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:*
cpe:2.3:a:bytecodealliance:cranelift-codegen:0.92.0:*:*:*:*:rust:*:*
cpe:2.3:a:bytecodealliance:cranelift-codegen:0.93.0:*:*:*:*:rust:*:*
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
cpe:2.3:a:bytecodealliance:wasmtime:5.0.0:*:*:*:*:rust:*:*
cpe:2.3:a:bytecodealliance:wasmtime:6.0.0:*:*:*:*:rust:*:*

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