CVE-2022-39393 Wasmtime vulnerable to data leakage between instances in the pooling allocator

What is CVE-2022-39393?

CVE-2022-39393 is a high-severity vulnerability in bytecodealliance wasmtime, published on 10 Nov 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. This bug has been patched and users should upgrade to Wasmtime 2.0.2 and 1.0.2. Other mitigations include disabling the pooling allocator and disabling the `memory-init-cow`.

Weakness: CWE-212, CWE-226

Which versions are affected by CVE-2022-39393?

6 open source packages ship an affected version, including wasmtime. It affects 1 product.

Products include Bytecodealliance Wasmtime.

How do I fix CVE-2022-39393?

Upgrade wasmtime to a fixed version for your release line: 1.0.2 or 2.0.2.

Is CVE-2022-39393 being exploited?

There is no known exploitation of CVE-2022-39393 in the wild and no public exploit code.

Other vulnerabilities in bytecodealliance wasmtime

• CVE-2026-34971 Wasmtime miscompiled guest heap access enables sandbox escape on aarch64 Cranelift Critical 9.0
• CVE-2026-34987 Wasmtime with Winch compiler backend on aarch64 may allow a sandbox-escaping memory access Critical 9.0
• CVE-2022-24791 Use after free in Wasmtime High 8.1
• CVE-2026-47261 Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` host restriction High 7.5
• CVE-2026-34941 Wasmtime has a Heap OOB read in component model UTF-16 to latin1+utf16 string transcoding Medium 6.9

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-wh6w-3828-g9qf, RUSTSEC-2022-0075, RUSTSEC-2022-0098, UBUNTU-CVE-2022-39393.