{"id":"CVE-2026-34944","state":"PUBLISHED","title":"Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64","description":"Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.","publishedAt":"2026-04-09T18:38:16.182Z","updatedAt":"2026-04-13T15:38:40.634Z","severity":{"score":4.1,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["bytecodealliance wasmtime"],"affected":[{"vendor":"bytecodealliance","product":"wasmtime","versions":[{"version":"< 24.0.7","status":"affected"},{"version":">= 25.0.0, < 36.0.7","status":"affected"},{"version":">= 37.0.0, < 42.0.2","status":"affected"},{"version":">= 43.0.0, < 44.0.1","status":"affected"}]}],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-qqfj-4vcm-26hv"],"weaknesses":["CWE-248"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/34xxx/CVE-2026-34944.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-34944","state":"PUBLISHED","datePublished":"2026-04-09T18:38:16.182Z","dateUpdated":"2026-04-13T15:38:40.634Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-31T17:27:08.660Z"},"containers":{"cna":{"title":"Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64","descriptions":[{"lang":"en","value":"Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1."}],"affected":[{"vendor":"bytecodealliance","product":"wasmtime","versions":[{"version":"< 24.0.7","status":"affected"},{"version":">= 25.0.0, < 36.0.7","status":"affected"},{"version":">= 37.0.0, < 42.0.2","status":"affected"},{"version":">= 43.0.0, < 44.0.1","status":"affected"}]}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-qqfj-4vcm-26hv","name":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-qqfj-4vcm-26hv","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"ACTIVE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":4.1,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-248","lang":"en","description":"CWE-248: Uncaught Exception","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-09T18:38:16.182Z"},"source":{"advisory":"GHSA-qqfj-4vcm-26hv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-13T15:06:23.130132Z","id":"CVE-2026-34944","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-13T15:38:40.634Z"}}]}}}