{"cve":"CVE-2026-34943","nvd":{"published":"2026-04-09T19:16:24.020","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 contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime's implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. 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:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":5.6},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-248"],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m758-wjhj-p3jq"],"products":["bytecodealliance:wasmtime"],"source":"nvd","synced_at":"2026-10-26T21:38:48.864438205+00:00"},"epss":{"cve":"CVE-2026-34943","score":0.00324,"percentile":0.2518,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-m758-wjhj-p3jq","url":"https://osv.dev/vulnerability/GHSA-m758-wjhj-p3jq","summary":"Wasmtime has a possible panic when lifting `flags` component value","modified":"2026-09-10T03:51:02.309749704Z","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-2026-0085","url":"https://osv.dev/vulnerability/RUSTSEC-2026-0085","summary":"Panic when lifting `flags` component value","modified":"2026-10-12T18:00:09.239209732Z","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."]}