Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend.
This issue is fixed in versions 36.0.19 and 43.0.0.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
References 7
https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9…
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8…
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/pull/12613
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/pull/14818
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0
security-advisories@github.com
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm…
security-advisories@github.com