{"id":"CVE-2026-34983","state":"PUBLISHED","title":"Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`","description":"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.","publishedAt":"2026-04-09T18:47:26.575Z","updatedAt":"2026-04-13T15:38:33.779Z","severity":{"score":1,"label":"Low","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["bytecodealliance wasmtime"],"affected":[{"vendor":"bytecodealliance","product":"wasmtime","versions":[{"version":">= 43.0.0, < 43.0.1","status":"affected"}]}],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/34xxx/CVE-2026-34983.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-34983","state":"PUBLISHED","datePublished":"2026-04-09T18:47:26.575Z","dateUpdated":"2026-04-13T15:38:33.779Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-31T19:38:31.617Z"},"containers":{"cna":{"title":"Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"bytecodealliance","product":"wasmtime","versions":[{"version":">= 43.0.0, < 43.0.1","status":"affected"}]}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2","name":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"PHYSICAL","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"HIGH","userInteraction":"ACTIVE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":1,"baseSeverity":"LOW","vectorString":"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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","description":"CWE-416: Use After Free","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-09T18:47:26.575Z"},"source":{"advisory":"GHSA-hfr4-7c6c-48w2","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-hfr4-7c6c-48w2","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-13T15:28:37.718395Z","id":"CVE-2026-34983","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-13T15:38:33.779Z"}}]}}}