{"cve":"CVE-2026-34942","nvd":{"published":"2026-04-09T19:16:23.857","modified":"2026-10-26T21:10:00.170","status":"Analyzed","description":"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.","cvss_v4":{"vector":"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","score":5.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-129"],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-jxhv-7h78-9775"],"products":["bytecodealliance:wasmtime"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-34942","score":0.00354,"percentile":0.28889,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-jxhv-7h78-9775","url":"https://osv.dev/vulnerability/GHSA-jxhv-7h78-9775","summary":"Wasmtime: Panic when transcoding misaligned utf-16 strings","modified":"2026-09-10T03:50:44.707558279Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":["<24.0.7"],"fixed":["24.0.7"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=25.0.0 <36.0.7"],"fixed":["36.0.7"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=37.0.0 <42.0.2"],"fixed":["42.0.2"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=43.0.0 <43.0.1"],"fixed":["43.0.1"]}]},{"id":"RUSTSEC-2026-0092","url":"https://osv.dev/vulnerability/RUSTSEC-2026-0092","summary":"Panic when transcoding misaligned component model UTF-16 strings","modified":"2026-10-12T18:00:13.065488323Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=0.0.0-0 <24.0.7",">=25.0.0 <36.0.7",">=37.0.0 <42.0.2",">=43.0.0 <43.0.1"],"fixed":["24.0.7","36.0.7","42.0.2","43.0.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}