{"id":"CVE-2026-34983","summary":"Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`","details":"Wasmtime is a runtime for WebAssembly. In 43.0.0, cloning a wasmtime::Linker is unsound and can result in use-after-free bugs. This bug is not controllable by guest Wasm programs. It can only be triggered by a specific sequence of embedder API calls made by the host. Specifically, the following steps must occur to trigger the bug clone a wasmtime::Linker, drop the original linker instance, use the new, cloned linker instance, resulting in a use-after-free. This vulnerability is fixed in 43.0.1.","aliases":["GHSA-hfr4-7c6c-48w2","PYSEC-2026-151","RUSTSEC-2026-0090"],"modified":"2026-07-08T08:12:57.063710005Z","published":"2026-04-09T18:47:26.575Z","related":["CGA-4cqx-28v6-cpr4"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34983.json","cwe_ids":["CWE-416"],"cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34983.json"},{"type":"ADVISORY","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34983"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bytecodealliance/wasmtime","events":[{"introduced":"be23469ece57c0be64904f12111c8d808b0ce4ac"},{"fixed":"cd4b6ed9b2a59cd3f317bff812126dd6a0e92dd2"}],"database_specific":{"cpe":"cpe:2.3:a:bytecodealliance:wasmtime:43.0.0:*:*:*:*:rust:*:*","extracted_events":[{"introduced":"43.0.0"},{"fixed":"43.0.1"},{"last_affected":"43.0.0"}],"source":["AFFECTED_FIELD","CPE_STRING"]}}],"versions":["43.0.0","v43.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34983.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:P/AC:H/AT:P/PR:H/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N"}]}