{"id":"CVE-2026-34942","aliases":["GHSA-jxhv-7h78-9775","RUSTSEC-2026-0092"],"url":"https://o3.security/vulnerability/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.","published":"2026-04-09T18:32:56.456Z","modified":"2026-08-07T11:31:08.197119454Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"crates.io","name":"wasmtime","fixedVersion":"24.0.7"},{"ecosystem":"crates.io","name":"wasmtime","fixedVersion":"36.0.7"},{"ecosystem":"crates.io","name":"wasmtime","fixedVersion":"42.0.2"},{"ecosystem":"crates.io","name":"wasmtime","fixedVersion":"43.0.1"}],"fix":null,"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-07T11:31:08.197119454Z"}}