{"cve":"CVE-2026-27572","nvd":{"published":"2026-02-24T22:16:32.687","modified":"2026-06-17T10:27:19.773","status":"Analyzed","description":"Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of the `wasi:http/types.fields` resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime's implementation in the `wasmtime-wasi-http` crate is backed by a data structure which panics when it reaches excessive capacity and this condition was not handled gracefully in Wasmtime. Panicking in a WASI implementation is a Denial of Service vector for embedders and is treated as a security vulnerability in Wasmtime. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 patch this vulnerability and return a trap to the guest instead of panicking. There are no known workarounds at this time. Embedders are encouraged to update to a patched version of Wasmtime.","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:H","score":6.9},"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-770"],"references":["https://docs.rs/http/1.4.0/http/header/#limitations","https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a","https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6","https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6","https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4"],"products":["bytecodealliance:wasmtime"],"source":"nvd","synced_at":"2026-10-19T22:24:17.937441719+00:00"},"epss":{"cve":"CVE-2026-27572","score":0.00519,"percentile":0.44101,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-243v-98vx-264h","url":"https://osv.dev/vulnerability/GHSA-243v-98vx-264h","summary":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","modified":"2026-09-10T03:50:33.728858201Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":["<24.0.6"],"fixed":["24.0.6"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=25.0.0 <36.0.6"],"fixed":["36.0.6"]},{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=37.0.0 <40.0.4"],"fixed":["40.0.4"]}]},{"id":"RUSTSEC-2026-0021","url":"https://osv.dev/vulnerability/RUSTSEC-2026-0021","summary":"Panic adding excessive fields to a `wasi:http/types.fields` instance","modified":"2026-10-12T18:00:13.556608408Z","packages":[{"ecosystem":"crates.io","name":"wasmtime","purl":"pkg:cargo/wasmtime","ranges":[">=0.0.0-0 <24.0.6",">=25.0.0 <36.0.6",">=37.0.0 <40.0.4",">=41.0.0 <41.0.4"],"fixed":["24.0.6","36.0.6","40.0.4","41.0.4"]}]}],"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."]}