{"id":"CVE-2026-34942","summary":"Wasmtime panics when transcoding misaligned utf-16 strings","details":"Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be passed to the host for transcoding which would trigger a host panic. This panic is possible to trigger from malicious guests which transfer very specific strings across components with specific addresses. Host panics are considered a DoS vector in Wasmtime as the panic conditions are controlled by the guest in this situation. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.","aliases":["GHSA-jxhv-7h78-9775","RUSTSEC-2026-0092"],"modified":"2026-07-15T01:49:07.703868927Z","published":"2026-04-09T18:32:56.456Z","related":["CGA-7f8x-xjfg-9cq8","SUSE-SU-2026:21789-1","openSUSE-SU-2026:20749-1"],"database_specific":{"cwe_ids":["CWE-129"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34942.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34942.json"},{"type":"ADVISORY","url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxhv-7h78-9775"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34942"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/bytecodealliance/wasmtime","events":[{"introduced":"0"},{"fixed":"a15daff0bfc965d1656ddcf9beaa1d085c3a7410"},{"introduced":"0b195ef5db76c02fb5392ec1418c58bdc5537d41"},{"fixed":"09539085b9b514b65d5c51e2905dc38f6eb414b9"},{"introduced":"7b3d6ae79e9153a2477668062f5622c10333925f"},{"fixed":"403f9929d4e13ed87c76471d4f4bc8d381c876eb"},{"introduced":"be23469ece57c0be64904f12111c8d808b0ce4ac"},{"fixed":"cd4b6ed9b2a59cd3f317bff812126dd6a0e92dd2"}],"database_specific":{"cpe":"cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*","extracted_events":[{"introduced":"0"},{"fixed":"24.0.7"},{"introduced":"25.0.0"},{"fixed":"36.0.7"},{"introduced":"37.0.0"},{"fixed":"42.0.2"},{"introduced":"43.0.0"},{"fixed":"43.0.1"}],"source":"CPE_RANGE"}}],"versions":["v43.0.0","v42.0.1","v36.0.6","v24.0.6","v42.0.0","v36.0.5","dev","v36.0.4","v24.0.5","v36.0.3","v36.0.2","v24.0.4","v36.0.1","v36.0.0","v24.0.3","v24.0.2","v24.0.1","v24.0.0","v0.35.0","v0.33.0","v0.34.0","v0.32.0","v0.31.0","v0.30.0","v0.29.0","v0.28.0","v0.27.0","v0.26.0","v0.25.0","v0.24.0","v0.23.0","v0.22.0","cranelift-v0.69.0","v0.21.0","v0.20.0","v0.19.0","v0.18.0","v0.17.0","v0.16.0","cranelift-v0.61.0","cranelift-v0.60.0","v0.12.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34942.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L"}]}