wasmtime is a fast and secure runtime for WebAssembly.
Priority LOW 21CWE-193Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00624 50th percentileScored 2026-11-07
Fix Fixed wasmtime (crates.io): 4.0.1, 5.0.1, 6.0.1cranelift-codegen (crates.io): 0.91.1, 0.92.1, 0.93.1
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| bytecodealliance | wasmtime | cranelift-codegen: >= 0.88.0, < 0.91.1; cranelift-codegen: >= 0.92.0, < 0.92.1; cranelift-codegen: >= 0.93.0, < 0.93.1; wasmtime: >= 0.37.0, < 4.0.1; wasmtime: >= 5.0.0, < 5.0.1; wasmtime: >= 6.0.0, < 6.0.1 | — | No fix listed | CNA |
| — | wasmtime (crates.io) | 1.0.0 to before 4.0.1 | 4.0.1 | Patch available | GHSA-xm67-587q-r2vw |
| — | wasmtime (crates.io) | 5.0.0 to before 5.0.1 | 5.0.1 | Patch available | GHSA-xm67-587q-r2vw |
| — | wasmtime (crates.io) | 6.0.0 to before 6.0.1 | 6.0.1 | Patch available | GHSA-xm67-587q-r2vw |
| — | cranelift-codegen (crates.io) | 0.88.0 to before 0.91.1 | 0.91.1 | Patch available | GHSA-xm67-587q-r2vw |
| — | cranelift-codegen (crates.io) | 0.92.0 to before 0.92.1 | 0.92.1 | Patch available | GHSA-xm67-587q-r2vw |
| — | cranelift-codegen (crates.io) | 0.93.0 to before 0.93.1 | 0.93.1 | Patch available | GHSA-xm67-587q-r2vw |
- wasmtime Vendorbytecodealliance Affected cranelift-codegen: >= 0.88.0, < 0.91.1; cranelift-codegen: >= 0.92.0, < 0.92.1; cranelift-codegen: >= 0.93.0, < 0.93.1; wasmtime: >= 0.37.0, < 4.0.1; wasmtime: >= 5.0.0, < 5.0.1; wasmtime: >= 6.0.0, < 6.0.1 Fixed in — No fix listed CNA
- wasmtime (crates.io) Vendor— Affected 1.0.0 to before 4.0.1 Fixed in 4.0.1 Patch available GHSA-xm67-587q-r2vw
- wasmtime (crates.io) Vendor— Affected 5.0.0 to before 5.0.1 Fixed in 5.0.1 Patch available GHSA-xm67-587q-r2vw
- wasmtime (crates.io) Vendor— Affected 6.0.0 to before 6.0.1 Fixed in 6.0.1 Patch available GHSA-xm67-587q-r2vw
- cranelift-codegen (crates.io) Vendor— Affected 0.88.0 to before 0.91.1 Fixed in 0.91.1 Patch available GHSA-xm67-587q-r2vw
- cranelift-codegen (crates.io) Vendor— Affected 0.92.0 to before 0.92.1 Fixed in 0.92.1 Patch available GHSA-xm67-587q-r2vw
- cranelift-codegen (crates.io) Vendor— Affected 0.93.0 to before 0.93.1 Fixed in 0.93.1 Patch available GHSA-xm67-587q-r2vw
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:* | 0.84.0 to before 0.91.1 | Vulnerable | bytecodealliance |
| cpe:2.3:a:bytecodealliance:cranelift-codegen:0.92.0:*:*:*:*:rust:*:* | 0.92.0 | Vulnerable | bytecodealliance |
| cpe:2.3:a:bytecodealliance:cranelift-codegen:0.93.0:*:*:*:*:rust:*:* | 0.93.0 | Vulnerable | bytecodealliance |
| cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* | 0.37.0 to before 4.0.1 | Vulnerable | bytecodealliance |
| cpe:2.3:a:bytecodealliance:wasmtime:5.0.0:*:*:*:*:rust:*:* | 5.0.0 | Vulnerable | bytecodealliance |
| cpe:2.3:a:bytecodealliance:wasmtime:6.0.0:*:*:*:*:rust:*:* | 6.0.0 | Vulnerable | bytecodealliance |
- cpe:2.3:a:bytecodealliance:cranelift-codegen:*:*:*:*:*:rust:*:* Versions 0.84.0 to before 0.91.1 Vulnerable ·bytecodealliance
- cpe:2.3:a:bytecodealliance:cranelift-codegen:0.92.0:*:*:*:*:rust:*:* Versions 0.92.0 Vulnerable ·bytecodealliance
- cpe:2.3:a:bytecodealliance:cranelift-codegen:0.93.0:*:*:*:*:rust:*:* Versions 0.93.0 Vulnerable ·bytecodealliance
- cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* Versions 0.37.0 to before 4.0.1 Vulnerable ·bytecodealliance
- cpe:2.3:a:bytecodealliance:wasmtime:5.0.0:*:*:*:*:rust:*:* Versions 5.0.0 Vulnerable ·bytecodealliance
- cpe:2.3:a:bytecodealliance:wasmtime:6.0.0:*:*:*:*:rust:*:* Versions 6.0.0 Vulnerable ·bytecodealliance
Remediation
- Fix · GHSA-xm67-587q-r2vw wasmtime (crates.io) Fixed in 4.0.1 Advisory →
- Fix · GHSA-xm67-587q-r2vw wasmtime (crates.io) Fixed in 5.0.1 Advisory →
- Fix · GHSA-xm67-587q-r2vw wasmtime (crates.io) Fixed in 6.0.1 Advisory →
- Fix · GHSA-xm67-587q-r2vw cranelift-codegen (crates.io) Fixed in 0.91.1 Advisory →
- Fix · GHSA-xm67-587q-r2vw cranelift-codegen (crates.io) Fixed in 0.92.1 Advisory →
- Fix · GHSA-xm67-587q-r2vw cranelift-codegen (crates.io) Fixed in 0.93.1 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2023-27477
- 2026-10-03 Alias added: GHSA-xm67-587q-r2vw
- 2026-11-04 EPSS moved to the 50th–90th percentile
References
Patch 2
Advisory 2
More bytecodealliance Cranelift-codegen vulnerabilities
- TI-2023-11636 Guest-controlled out-of-bounds read/write on x86_64 in wasmtime CVSS 3.1CRITICAL 10.0
- TI-2022-13189 Use After Free in Wasmtime CVSS 3.1HIGH 8.8
- TI-2021-12298 Memory access due to code generation flaw in Cranelift module CVSS 3.1HIGH 8.8
- TI-2022-13211 Cranelift vulnerable to miscompilation of constant values in division on AArch64 CVSS 3.1HIGH 7.5
- TI-2022-13148 Miscompilation of `i8x16.swizzle` and `select` with v128 inputs in Wasmtime CVSS 3.1MEDIUM 5.6
Sources
- CVE-2023-27477 · CVE Program
- CVE-2023-27477 · NVD
- FIRST EPSS
- GHSA-xm67-587q-r2vw · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences