Vulnerability record · CVE-2023-27477 · published 8 March 2023
CVE-2023-27477: Bytecodealliance cranelift-codegen vulnerability
Bytecodealliance · Cranelift Codegen
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.
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Affected products
2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.wasm_simd | Product |
| https://github.com/bytecodealliance/wasmtime/commit/5dc2bbccbb363e474d2c9a1b8e38a89a43bbd5d1 | Patch |
| https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-xm67-587q-r2vw | MitigationPatchVendor Advisory |
| https://github.com/webassembly/simd | Not Applicable |
| https://groups.google.com/a/bytecodealliance.org/g/sec-announce/c/Mov-ItrNJsQ | Mailing ListRelease NotesVendor Advisory |
| https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.wasm_simd | Product |
| https://github.com/bytecodealliance/wasmtime/commit/5dc2bbccbb363e474d2c9a1b8e38a89a43bbd5d1 | Patch |
| https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-xm67-587q-r2vw | MitigationPatchVendor Advisory |
| https://github.com/webassembly/simd | Not Applicable |
| https://groups.google.com/a/bytecodealliance.org/g/sec-announce/c/Mov-ItrNJsQ | Mailing ListRelease NotesVendor Advisory |
Track CVE-2023-27477 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2023-27477), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.
