CVE-2026-115893
Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
- State
- Published
- Severity
- 9.9 Critical
- Published
- Oct 23, 2026
- Updated
- Oct 29, 2026
- Reserved
- Oct 23, 2026
Description
Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm br_table instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary other code at a user-controlled offset, allowing a user-controlled Wasm module to escape the sandbox on aarch64 engines using the default Cranelift backend. This issue is fixed in versions 36.0.19, 48.0.7, and 49.0.4.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.9 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H | GitHub_M |
Weaknesses
- CWE-691 Insufficient Control Flow Management
Affected Products
| Product | Versions |
|---|---|
wasmtimebytecodealliance |
|
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-mghf-wjfp-p5xm
- https://github.com/bytecodealliance/wasmtime/pull/14818
- https://github.com/bytecodealliance/wasmtime/pull/14819
- https://github.com/bytecodealliance/wasmtime/pull/14820
- https://github.com/bytecodealliance/wasmtime/pull/14826
- https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd
- https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618
- https://github.com/bytecodealliance/wasmtime/commit/e61df1b454be9313d61a5f8de07722a421139bbe
- https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa
- https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19
- https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7
- https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4
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