{"id":"CVE-2026-115892","aliases":["EUVD-2026-109187","GHSA-9pvw-hwfg-92h5","RUSTSEC-2026-0378","UBUNTU-CVE-2026-115892"],"status":"published","title":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","severity":{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00434,"percentile":0.38122,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-248","CWE-843"],"published":"2026-10-19T12:00:00Z","modified":"2026-10-31T02:31:00Z","fixes":[{"ecosystem":"crates.io","package":"wasmtime","fixed_in":["48.0.7","49.0.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"46.0.0"},{"fixed":"48.0.7"}]}]},{"source":"ghsa","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"49.0.0"},{"fixed":"49.0.4"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"46.0.0"},{"fixed":"48.0.7"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"49.0.0"},{"fixed":"49.0.4"}]}]},{"source":"osv","ecosystem":"crates.io","package":"wasmtime","ranges":[{"type":"SEMVER","events":[{"introduced":"46.0.0"},{"fixed":"48.0.7"},{"introduced":"49.0.0"},{"fixed":"49.0.4"}]}]},{"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: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-9pvw-hwfg-92h5","tags":["x_refsource_CONFIRM","advisory","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14819","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14820","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/pull/14827","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/commit/48dacc76241f06088e79f3ce1b17642f2f7bf158","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v48.0.7","tags":["x_refsource_MISC","web","report"]},{"url":"https://github.com/bytecodealliance/wasmtime/releases/tag/v49.0.4","tags":["x_refsource_MISC","web","report"]},{"url":"https://rustsec.org/advisories/RUSTSEC-2026-0378.html","tags":["web","advisory"]},{"url":"https://github.com/advisories/GHSA-9pvw-hwfg-92h5"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/115xxx/CVE-2026-115892.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115892","tags":["advisory"]},{"url":"https://github.com/bytecodealliance/wasmtime","tags":["package"]},{"url":"https://crates.io/crates/wasmtime","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-115892","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-115892","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-115892","title":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","status":"published","published":"2026-10-23T21:26:54.528Z","modified":"2026-10-29T14:44:33.323Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-843","CWE-248"],"updated_at":"2026-11-02T14:20:01.618694Z"}],"euvd":[{"id":"EUVD-2026-109187","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","status":"published","published":"2026-10-23T21:26:54Z","modified":"2026-10-29T14:44:33Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:59:16.484344Z"}],"ghsa":[{"id":"GHSA-9pvw-hwfg-92h5","title":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"### Summary\n\nWasmtime may panic when the host lowers a component model `stream` or `future` into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type such as `StreamAny` or `FutureAny`, and then passes it to a guest function with a different payload type.\n\nGHSA-63h4-6cx9-pjfj is a related advisory also fixing issues within this area, and this advisory is being issued for portions of Wasmtime that were not fixed as part of that advisory.\n\n### Impact\n\nThis affects embedders that do all of the following:\n\n1. Create streams or futures on the host with `StreamReader::new` or `FutureReader::new`\n2. Pass them to guest code and receive them back as `StreamAny`, `FutureAny`, `Val::Stream`/`Val::Future`, or a typed reader whose payload is one of these.\n3. Pass them on to a guest function whose `stream` or `future` payload type differs from the type the host created them with.\n\nA guest can cause the mismatch in step 3 when it controls the types of the functions it exports or of the values it returns. In that case a malicious guest can make the host panic, a denial of service. Embedders that only use statically typed `StreamReader\u003cT\u003e`/`FutureReader\u003cT\u003e` with concrete payload types throughout, or that never pass streams or futures they created through a guest and back, are not affected.","status":"published","published":"2026-10-23T22:04:45Z","modified":"2026-10-23T22:04:47Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-843"],"updated_at":"2026-11-02T14:41:35.723785Z"}],"nvd":[{"id":"CVE-2026-115892","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","status":"published","published":"2026-10-23T22:16:58.633Z","modified":"2026-10-29T15:17:19.493Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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"}],"cwes":["CWE-248","CWE-843"],"updated_at":"2026-11-02T14:13:03.126833Z"}],"osv":[{"id":"CVE-2026-115892","title":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","status":"published","published":"2026-10-23T21:26:54.528Z","modified":"2026-10-31T02:31:00.16963986Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-248","CWE-843"],"updated_at":"2026-11-02T15:44:56.675758Z"},{"id":"GHSA-9pvw-hwfg-92h5","title":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"### Summary\n\nWasmtime may panic when the host lowers a component model `stream` or `future` into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type such as `StreamAny` or `FutureAny`, and then passes it to a guest function with a different payload type.\n\nGHSA-63h4-6cx9-pjfj is a related advisory also fixing issues within this area, and this advisory is being issued for portions of Wasmtime that were not fixed as part of that advisory.\n\n### Impact\n\nThis affects embedders that do all of the following:\n\n1. Create streams or futures on the host with `StreamReader::new` or `FutureReader::new`\n2. Pass them to guest code and receive them back as `StreamAny`, `FutureAny`, `Val::Stream`/`Val::Future`, or a typed reader whose payload is one of these.\n3. Pass them on to a guest function whose `stream` or `future` payload type differs from the type the host created them with.\n\nA guest can cause the mismatch in step 3 when it controls the types of the functions it exports or of the values it returns. In that case a malicious guest can make the host panic, a denial of service. Embedders that only use statically typed `StreamReader\u003cT\u003e`/`FutureReader\u003cT\u003e` with concrete payload types throughout, or that never pass streams or futures they created through a guest and back, are not affected.","status":"published","published":"2026-10-23T22:04:45Z","modified":"2026-10-23T22:25:32.52671355Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-843"],"updated_at":"2026-11-02T15:46:43.875515Z"},{"id":"RUSTSEC-2026-0378","title":"Panic lowering a host-created component model stream into a guest that expects a different payload type","description":"This is an entry in the RustSec database for the Wasmtime security advisory\nlocated at\nhttps://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-9pvw-hwfg-92h5\nFor more information see the GitHub-hosted security advisory.","status":"published","published":"2026-10-19T12:00:00Z","modified":"2026-10-24T06:25:41Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T15:53:40.430679Z"},{"id":"UBUNTU-CVE-2026-115892","description":"Wasmtime is a runtime for WebAssembly. From 46.0.0 until 48.0.7 and 49.0.4, lowering a host-created component-model stream or future into a guest can omit a required payload-type check after the value passes through guest code and returns through StreamAny, FutureAny, Val::Stream, Val::Future, or an equivalent typed reader. A malicious guest that controls exported function types or returned values can cause the host to pass the type-erased value to a guest expecting a different payload type, which panics the Wasmtime host. This issue is fixed in versions 48.0.7 and 49.0.4.","status":"published","published":"2026-10-23T22:16:00Z","modified":"2026-10-28T17:50:38Z","cvss":[{"version":"4.0","score":5.7,"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T16:56:00.081948Z"}]}}