{"id":"CVE-2026-27572","aliases":["DEBIAN-CVE-2026-27572","EUVD-2026-8569","GHSA-243v-98vx-264h","JLSEC-2026-1353","RUSTSEC-2026-0021","UBUNTU-CVE-2026-27572"],"status":"published","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","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.","severity":{"version":"4.0","score":6.9,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00519,"percentile":0.44584,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-02-24T12:00:00Z","modified":"2026-10-28T02:30:24Z","fixes":[{"ecosystem":"crates.io","package":"wasmtime","fixed_in":["24.0.6","36.0.6","40.0.4","41.0.4"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:14","package":"rust-wasmtime","fixed_in":["36.0.6+dfsg-1"],"sources":["osv"]},{"ecosystem":"Julia","package":"Wasmtime_jll","fixed_in":["45.0.1+0"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"24.0.6"}]}]},{"source":"ghsa","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"25.0.0"},{"fixed":"36.0.6"}]}]},{"source":"ghsa","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"37.0.0"},{"fixed":"40.0.4"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["26.0.1+dfsg-10","26.0.1+dfsg-3","26.0.1+dfsg-4","26.0.1+dfsg-5","26.0.1+dfsg-6","26.0.1+dfsg-7","26.0.1+dfsg-8","26.0.1+dfsg-9","27.0.0+dfsg-2","27.0.0+dfsg-3","27.0.0+dfsg-4","28.0.1+dfsg-1","28.0.1+dfsg-2","28.0.1+dfsg-3","29.0.1+dfsg-1","29.0.1+dfsg-2","29.0.1+dfsg-3","29.0.1+dfsg-4","29.0.1+dfsg-5","29.0.1+dfsg-6","29.0.1+dfsg-7","29.0.1+dfsg-8","36.0.11+dfsg-1","36.0.12+dfsg-1","36.0.12+dfsg-2","36.0.12+dfsg-3","36.0.13+dfsg-1","36.0.5+dfsg-1","36.0.5+dfsg-2","36.0.5+dfsg-3","36.0.5+dfsg-4","36.0.5+dfsg-5","36.0.6+dfsg-1","36.0.6+dfsg-2","36.0.6+dfsg-3","36.0.6+dfsg-4","36.0.6+dfsg-5","36.0.6+dfsg-6","36.0.6+dfsg-7","36.0.7+dfsg-1","36.0.8+dfsg-1","36.0.9+dfsg-1","36.0.9+dfsg-2"]},{"source":"osv","ecosystem":"Debian:14","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"36.0.6+dfsg-1"}]}],"versions":["26.0.1+dfsg-10","26.0.1+dfsg-3","26.0.1+dfsg-4","26.0.1+dfsg-5","26.0.1+dfsg-6","26.0.1+dfsg-7","26.0.1+dfsg-8","26.0.1+dfsg-9","27.0.0+dfsg-2","27.0.0+dfsg-3","27.0.0+dfsg-4","28.0.1+dfsg-1","28.0.1+dfsg-2","28.0.1+dfsg-3","29.0.1+dfsg-1","29.0.1+dfsg-2","29.0.1+dfsg-3","29.0.1+dfsg-4","29.0.1+dfsg-5","29.0.1+dfsg-6","29.0.1+dfsg-7","29.0.1+dfsg-8","36.0.5+dfsg-1","36.0.5+dfsg-2","36.0.5+dfsg-3","36.0.5+dfsg-4","36.0.5+dfsg-5"]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"24.0.6"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"25.0.0"},{"fixed":"36.0.6"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"37.0.0"},{"fixed":"40.0.4"}]}]},{"source":"osv","ecosystem":"Julia","package":"Wasmtime_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"45.0.1+0"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"24.0.6"},{"introduced":"25.0.0"},{"fixed":"36.0.6"},{"introduced":"37.0.0"},{"fixed":"40.0.4"},{"introduced":"41.0.0"},{"fixed":"41.0.4"}]}]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["10.0.1+dfsg-7","15.0.1+dfsg-4","16.0.0+dfsg-2","16.0.0+dfsg-3"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["26.0.1+dfsg-3"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["36.0.5+dfsg-1","36.0.13+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"rust-wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["26.0.1+dfsg-3","26.0.1+dfsg-4","28.0.1+dfsg-3","29.0.1+dfsg-5","36.0.5+dfsg-1"]}],"products":[{"vendor":"bytecodealliance","product":"wasmtime"}],"references":[{"url":"https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h","tags":["x_refsource_CONFIRM","Third Party Advisory","advisory","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a","tags":["x_refsource_MISC","Patch","fix","web","report"]},{"url":"https://docs.rs/http/1.4.0/http/header/#limitations","tags":["x_refsource_MISC","Not Applicable","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4","tags":["x_refsource_MISC","Product","Release Notes","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27572","tags":["advisory","web"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0021.html","tags":["web","advisory","report"]},{"url":"https://github.com/advisories/GHSA-243v-98vx-264h","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27572.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-27572","tags":["advisory"]},{"url":"https://github.com/bytecodealliance/wasmtime","tags":["package"]},{"url":"https://crates.io/crates/wasmtime","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-27572","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-27572","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-27572","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","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.","status":"published","published":"2026-02-24T21:31:50.186Z","modified":"2026-02-27T20:55:29.879Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:19:49.199185Z"}],"euvd":[{"id":"EUVD-2026-8569","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.","status":"published","published":"2026-02-24T21:31:50Z","modified":"2026-02-27T20:55:29Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"updated_at":"2026-11-02T19:48:13.147525Z"}],"ghsa":[{"id":"GHSA-243v-98vx-264h","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","description":"### Impact\n\nWasmtime'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.\n\n### Patches\n\nWasmtime 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.\n\n### Workarounds\n\nThere are no known workarounds at this time, embedders are encouraged to update to a patched version of Wasmtime.\n\n### Resources\n\n* [Limitations of `http::HeaderMap`](https://docs.rs/http/1.4.0/http/header/#limitations)","status":"published","published":"2026-02-24T21:08:06Z","modified":"2026-02-27T20:25:49Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:39:28.962954Z"}],"nvd":[{"id":"CVE-2026-27572","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.","status":"published","published":"2026-02-24T22:16:32.687Z","modified":"2026-06-17T10:27:19.773Z","cvss":[{"version":"4.0","score":6.9,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:07.027269Z"}],"osv":[{"id":"CVE-2026-27572","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","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.","status":"published","published":"2026-02-24T21:31:50.186Z","modified":"2026-10-28T02:30:24.15733469Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:00.180685Z"},{"id":"DEBIAN-CVE-2026-27572","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.","status":"published","published":"2026-02-24T22:16:32.687Z","modified":"2026-10-01T03:03:01.102262333Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:53.877573Z"},{"id":"GHSA-243v-98vx-264h","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","description":"### Impact\n\nWasmtime'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.\n\n### Patches\n\nWasmtime 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.\n\n### Workarounds\n\nThere are no known workarounds at this time, embedders are encouraged to update to a patched version of Wasmtime.\n\n### Resources\n\n* [Limitations of `http::HeaderMap`](https://docs.rs/http/1.4.0/http/header/#limitations)","status":"published","published":"2026-02-24T21:08:06Z","modified":"2026-09-10T03:50:33.728858201Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:33.520522Z"},{"id":"JLSEC-2026-1353","title":"Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance","description":"### Impact\n\nWasmtime'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.\n\n### Patches\n\nWasmtime 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.\n\n### Workarounds\n\nThere are no known workarounds at this time, embedders are encouraged to update to a patched version of Wasmtime.\n\n### Resources\n\n  - [Limitations of `http::HeaderMap`](https://docs.rs/http/1.4.0/http/header/#limitations)","status":"published","published":"2026-08-21T20:43:33.133Z","modified":"2026-08-21T21:14:20.644203302Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"4.0","score":6.9,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium"}],"updated_at":"2026-11-02T15:47:18.159338Z"},{"id":"RUSTSEC-2026-0021","title":"Panic adding excessive fields to a `wasi:http/types.fields` instance","description":"This is an entry in the RustSec database for the Wasmtime security advisory\nlocated at\nhttps://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h\nFor more information see the GitHub-hosted security advisory.","status":"published","published":"2026-02-24T12:00:00Z","modified":"2026-10-12T18:00:13.556608408Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"}],"updated_at":"2026-11-02T15:53:40.430679Z"},{"id":"UBUNTU-CVE-2026-27572","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.","status":"published","published":"2026-02-24T22:16:00Z","modified":"2026-10-17T12:58:49.599390255Z","cvss":[{"version":"4.0","score":6.9,"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","level":"medium"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T16:56:08.726452Z"}]}}