Panic adding excessive fields to a `wasi:http/types.fields` instance

{
  "id": "1f15b070090002e99dc38988835999f0c2ed85ce9c88f17a4bab6779c50a1108",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2026-0021",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Panic adding excessive fields to a `wasi:http/types.fields` instance",
    "summary": "This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h For more information see the GitHub-hosted security advisory.",
    "evidence": "osv:RUSTSEC-2026-0021",
    "products": [
      {
        "name": {
          "value": "wasmtime",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "24.0.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "36.0.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "40.0.4",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "41.0.4",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "RUSTSEC-2026-0021",
      "aliases": [
        "CVE-2026-27572",
        "GHSA-243v-98vx-264h",
        "RUSTSEC-2026-0021"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "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"
                }
              ]
            }
          ],
          "package": {
            "name": "wasmtime",
            "purl": "pkg:cargo/wasmtime",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": "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",
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0021.json",
            "categories": [],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": []
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-12T18:00:13.556608408Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/wasmtime",
        "https://rustsec.org/advisories/RUSTSEC-2026-0021.html",
        "https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a"
      ],
      "provider_metadata": {
        "license": "CC0-1.0"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27572",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 306445,
  "published_at": "2026-02-24T12:00:00+00:00"
}