{"id":"CVE-2021-39219","published":"2021-09-17T20:10:13Z","modified":"2024-08-04T01:58:18Z","title":"Wrong type for `Linker`-define functions when used across two `Engine`s","vendor":"bytecodealliance","product":"wasmtime","tier":"tail","description":{"text":"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`.","provenance":"source","from":"CVE.org"},"cvss":{"score":6.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.00361,"percentile":0.2985,"provenance":"source"},"cwes":[{"id":"CWE-843","name":"Access of Resource Using Incompatible Type"}],"references":[{"url":"https://crates.io/crates/wasmtime","tags":["x_refsource_MISC"]},{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q879-9g95-56mx","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/bytecodealliance/wasmtime/commit/b39f087414f27ae40c44449ed5d1154e03449bff","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z2Z33FTXFQ6EOINVEQIP4DFBG53G5XIY/","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WAVBRYDDUIY2ZR3K3FO4BVYJKIMJ5TP7/","tags":["vendor-advisory","x_refsource_FEDORA"]}],"priority":{"score":10.4,"factors":[{"name":"EPSS percentile","points":5.97},{"name":"CVSS severity","points":4.41}]},"vendorSlug":"bytecodealliance","affectedVersions":[{"vendor":"bytecodealliance","product":"wasmtime","versions":["<= 0.29.0"]}],"affected":[{"ecosystem":"crates.io","package":"wasmtime","vulnerableRanges":["<0.30.0",">=0.0.0-0, <0.30.0"],"patched":["0.30.0"],"from":["GHSA-q879-9g95-56mx","RUSTSEC-2021-0110"],"provenance":"source"},{"ecosystem":"PyPI","package":"wasmtime","vulnerableRanges":["<0.30.0"],"patched":["0.30.0"],"from":["GHSA-q879-9g95-56mx","PYSEC-2021-320","PYSEC-2021-321","PYSEC-2021-322"],"provenance":"source"}],"euvd":{"id":"EUVD-2021-0465","exploited":false,"provenance":"source"},"lineage":{"familyId":"fam-bytecodealliance-wasmtime-cve-2021-39216","parents":[{"from":"CVE-2021-39216","to":"CVE-2021-39219","relation":"related","confidence":"high","kind":"lineage","evidence":[{"kind":"osv-related","provenance":"source","id":"GHSA-q879-9g95-56mx","via":"reference","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q879-9g95-56mx"},{"kind":"osv-related","provenance":"source","id":"GHSA-v4cp-h94r-m7xf","via":"reference","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-v4cp-h94r-m7xf"},{"kind":"same-code","provenance":"machine","files":["crates/wasmtime/src/func.rs"],"commits":["https://github.com/bytecodealliance/wasmtime/commit/101998733b74624cbd348a2366d05760b40181f3","https://github.com/bytecodealliance/wasmtime/commit/b39f087414f27ae40c44449ed5d1154e03449bff"],"basis":"rarely changed file"}]},{"from":"CVE-2021-39218","to":"CVE-2021-39219","relation":"related","confidence":"high","kind":"lineage","evidence":[{"kind":"osv-related","provenance":"source","id":"GHSA-4873-36h9-wv49","via":"reference","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-4873-36h9-wv49"},{"kind":"osv-related","provenance":"source","id":"GHSA-q879-9g95-56mx","via":"reference","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q879-9g95-56mx"}]}]}}