{"id":"CVE-2026-115889","aliases":[],"cve":{"records":[{"id":"CVE-2026-115889","source":"GitHub_M","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-10-23T19:37:27.176Z","published":"2026-10-23T21:23:27.669Z","modified":"2026-10-26T17:42:15.319Z"}],"publishers":[{"name":"GitHub_M","role":"CNA","organizationId":"a0819718-46f1-4df5-94e2-005712e83aaa","modified":"2026-10-23T21:23:27.669Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-10-26T17:42:15.319Z"}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm","tags":["x_refsource_CONFIRM"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/pull/12613","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14818","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19","tags":["x_refsource_MISC"],"source":"GitHub_M"},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0","tags":["x_refsource_MISC"],"source":"GitHub_M"}],"weaknesses":[{"id":"CWE-197","description":"CWE-197: Numeric Truncation Error","source":"GitHub_M"},{"id":"CWE-843","description":"CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')","source":"GitHub_M"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-10-26T15:40:36.390562Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"no"},{"name":"Technical Impact","value":"total"}]}]},"title":"Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation","titleSource":"GitHub_M","descriptionSource":"GitHub_M","description":"Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.","score":9.9,"severity":"critical","published":"2026-10-23T21:23:27.669Z","modified":"2026-10-26T17:42:15.319Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"bytecodealliance","name":"wasmtime","platforms":[],"versions":[{"version":"< 36.0.19","status":"affected"},{"version":">= 37.0.0, < 43.0.0","status":"affected"}],"cpes":[],"source":"GitHub_M","url":"https://www.cve.org/CVERecord?id=CVE-2026-115889"}],"remediation":[],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxm","https://github.com/bytecodealliance/wasmtime/pull/12613","https://github.com/bytecodealliance/wasmtime/pull/14818","https://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0","https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa","https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19","https://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0"],"sources":[{"name":"CVE","id":"CVE-2026-115889","modified":"2026-10-26T17:42:15.319Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-115889"}],"assessments":[{"source":"GitHub_M","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":9.9}],"sourceAffected":[],"observedAt":"2026-10-29T14:34:34.638Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T13:15:30.844Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[],"aiSummary":{"text":"Wasmtime versions before 36.0.19 and 43.0.0 have a bit-packing issue in the Cranelift compiler, causing silent overflows and miscompilation. This can lead to type confusion and other attacker-controlled effects. The issue is fixed in versions 36.0.19 and 43.0.0.","model":"@cf/meta/llama-3.3-70b-instruct-fp8-fast","generatedAt":"2026-10-30T09:22:48.803Z","sources":[{"name":"CVE","url":"https://www.cve.org/CVERecord?id=CVE-2026-115889"}]}}