CVE-2026-27572Wasmtime is a runtime for WebAssembly.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-770
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
bytecodealliance wasmtime bytecodealliance:wasmtime | before 24.0.6; from 25.0.0 before 36.0.6; from 37.0.0 before 40.0.4; from 41.0.0 before 41.0.4 | NVD |
References
- https://docs.rs/http/1.4.0/http/header/#limitationsnot-applicable
- https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0apatch
- https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6product, release-notes
- https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6product, release-notes
- https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4product, release-notes
- https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4product, release-notes
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264hthird-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.