CVE-2023-30624 – Wasmtime has Undefined Behavior in Rust runtime functions

https://notcve.org/view.php?id=CVE-2023-30624

Wasmtime is a standalone runtime for WebAssembly. Prior to versions 6.0.2, 7.0.1, and 8.0.1, Wasmtime's implementation of managing per-instance state, such as tables and memories, contains LLVM-level undefined behavior. This undefined behavior was found to cause runtime-level issues when compiled with LLVM 16 which causes some writes, which are critical for correctness, to be optimized away. Vulnerable versions of Wasmtime compiled with Rust 1.70, which is currently in beta, or later are known to have incorrectly compiled functions. Versions of Wasmtime compiled with the current Rust stable release, 1.69, and prior are not known at this time to have any issues, but can theoretically exhibit potential issues. The underlying problem is that Wasmtime's runtime state for an instance involves a Rust-defined structure called `Instance` which has a trailing `VMContext` structure after it. • https://github.com/bytecodealliance/wasmtime/commit/0977952dcd9d482bff7c288868ccb52769b3a92e https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-ch89-5g45-qwc7 • CWE-758: Reliance on Undefined, Unspecified, or Implementation-Defined Behavior •