{"cve":"CVE-2026-34946","nvd":{"published":"2026-04-09T19:16:24.490","modified":"2026-10-26T22:10:00.163","status":"Analyzed","description":"Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a vulnerability where the compilation of the table.fill instruction can result in a host panic. This means that a valid guest can be compiled with Winch, on any architecture, and cause the host to panic. This represents a denial-of-service vulnerability in Wasmtime due to guests being able to trigger a panic. The specific issue is that a historical refactoring changed how compiled code referenced tables within the table.* instructions. This refactoring forgot to update the Winch code paths associated as well, meaning that Winch was using the wrong indexing scheme. Due to the feature support of Winch the only problem that can result is tables being mixed up or nonexistent tables being used, meaning that the guest is limited to panicking the host (using a nonexistent table), or executing spec-incorrect behavior and modifying the wrong table. This vulnerability is fixed in 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:N","score":5.9},"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-670"],"references":["https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q49f-xg75-m9xw"],"products":["bytecodealliance:wasmtime"],"source":"nvd","synced_at":"2026-10-26T22:26:44.656832877+00:00"},"epss":{"cve":"CVE-2026-34946","score":0.00358,"percentile":0.29275,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-q49f-xg75-m9xw","url":"https://osv.dev/vulnerability/GHSA-q49f-xg75-m9xw","summary":"Wasmtime has host panic when Winch compiler executes `table.fill`","modified":"2026-09-10T03:51:02.711372857Z","packages":[{"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-2026-0089","url":"https://osv.dev/vulnerability/RUSTSEC-2026-0089","summary":"Host panic when Winch compiler executes `table.fill`","modified":"2026-10-12T18:00:13.553340442Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=0.0.0-0 <36.0.7",">=37.0.0 <42.0.2",">=43.0.0 <43.0.1"],"fixed":["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."]}