CVE-2023-27477wasmtime is a fast and secure runtime for WebAssembly. Wasmtime's code generation backend, Cranelift, has a bug on x86_64 platforms for…
- 3.1LowCVSS base score
- 0.62%Exploitation in 30 daysEPSS · top 49% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By GitHub_M
- 7 days later
· 7 days later
Published
- 24 months later
· 24 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Low3.1 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.62% · top 49% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.1.
Affected products
- affected cranelift-codegen: >= 0.88.0, < 0.91.1
- affected cranelift-codegen: >= 0.92.0, < 0.92.1
- affected cranelift-codegen: >= 0.93.0, < 0.93.1
- affected wasmtime: >= 0.37.0, < 4.0.1
- affected wasmtime: >= 5.0.0, < 5.0.1
- affected wasmtime: >= 6.0.0, < 6.0.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- crates.iocranelift-codegenGHSA-xm67-587q-r2vw (opens in a new tab)
- crates.iowasmtimeGHSA-xm67-587q-r2vw (opens in a new tab)
References
References5
- https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.wasm_simd (opens in a new tab)x_transferred
- https://github.com/webassembly/simd (opens in a new tab)x_transferred
- https://groups.google.com/a/bytecodealliance.org/g/sec-announce/c/Mov-ItrNJsQ (opens in a new tab)x_transferred
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-xm67-587q-r2vw (opens in a new tab)x_transferred
- https://github.com/bytecodealliance/wasmtime/commit/5dc2bbccbb363e474d2c9a1b8e38a89a43bbd5d1 (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-1143 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-xm67-587q-r2vw (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-27477)Record last updated .