| Vulnerability Name: | CVE-2021-39219 (CCN-209624) | ||||||||||||
| Assigned: | 2021-09-17 | ||||||||||||
| Published: | 2021-09-17 | ||||||||||||
| Updated: | 2021-12-21 | ||||||||||||
| Summary: | Wasmtime is an open source runtime for WebAssembly & WASI. Wasmtime before version 0.30.0 is affected by a type confusion vulnerability. As a Rust library the `wasmtime` crate clearly marks which functions are safe and which are `unsafe`, guaranteeing that if consumers never use `unsafe` then it should not be possible to have memory unsafety issues in their embeddings of Wasmtime. An issue was discovered in the safe API of `Linker::func_*` APIs. These APIs were previously not sound when one `Engine` was used to create the `Linker` and then a different `Engine` was used to create a `Store` and then the `Linker` was used to instantiate a module into that `Store`. Cross-`Engine` usage of functions is not supported in Wasmtime and this can result in type confusion of function pointers, resulting in being able to safely call a function with the wrong type. Triggering this bug requires using at least two `Engine` values in an embedding and then additionally using two different values with a `Linker` (one at the creation time of the `Linker` and another when instantiating a module with the `Linker`). It's expected that usage of more-than-one `Engine` in an embedding is relatively rare since an `Engine` is intended to be a globally shared resource, so the expectation is that the impact of this issue is relatively small. The fix implemented is to change this behavior to `panic!()` in Rust instead of silently allowing it. Using different `Engine` instances with a `Linker` is a programmer bug that `wasmtime` catches at runtime. This bug has been patched and users should upgrade to Wasmtime version 0.30.0. If you cannot upgrade Wasmtime and are using more than one `Engine` in your embedding it's recommended to instead use only one `Engine` for the entire program if possible. An `Engine` is designed to be a globally shared resource that is suitable to have only one for the lifetime of an entire process. If using multiple `Engine`s is required then code should be audited to ensure that `Linker` is only used with one `Engine`. | ||||||||||||
| CVSS v3 Severity: | 6.3 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H) 5.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H/E:U/RL:O/RC:C)
5.5 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H/E:U/RL:O/RC:C)
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| CVSS v2 Severity: | 3.3 Low (CVSS v2 Vector: AV:L/AC:M/Au:N/C:N/I:P/A:P)
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| Vulnerability Type: | CWE-843 | ||||||||||||
| Vulnerability Consequences: | Bypass Security | ||||||||||||
| References: | Source: MITRE Type: CNA CVE-2021-39219 Source: MISC Type: Product https://crates.io/crates/wasmtime Source: XF Type: UNKNOWN wasmtime-cve202139219-sec-bypass(209624) Source: CCN Type: Wasmtime GIT Repository Wasmtime Source: MISC Type: Patch, Third Party Advisory https://github.com/bytecodealliance/wasmtime/commit/b39f087414f27ae40c44449ed5d1154e03449bff Source: CCN Type: Wasmtime GIT Repository Wrong type for `Linker`-define functions when used across two `Engine`s Source: CONFIRM Type: Third Party Advisory https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q879-9g95-56mx Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-1805eacb48 Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-68713440cb | ||||||||||||
| Vulnerable Configuration: | Configuration 1: Configuration 2:  Denotes that component is vulnerable | ||||||||||||
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