Vulnerability-Lookup

CVE-2026-27572 (GCVE-0-2026-27572)

Vulnerability from cvelistv5 – Published: 2026-02-24 21:31 – Updated: 2026-02-27 20:55

Title

Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance

Summary

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 ?

6.9 (Medium)


                        
                          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

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M

References

URL

Tags

	https://github.com/bytecodealliance/wasmtime/secu…	x_refsource_CONFIRM
	https://github.com/bytecodealliance/wasmtime/comm…	x_refsource_MISC
	https://docs.rs/http/1.4.0/http/header/#limitations	x_refsource_MISC
	https://github.com/bytecodealliance/wasmtime/rele…	x_refsource_MISC
	https://github.com/bytecodealliance/wasmtime/rele…	x_refsource_MISC
	https://github.com/bytecodealliance/wasmtime/rele…	x_refsource_MISC
	https://github.com/bytecodealliance/wasmtime/rele…	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	bytecodealliance	wasmtime	Affected: < 24.0.6 Affected: >= 25.0.0, < 36.0.6 Affected: >= 37.0.0, < 40.0.4 Affected: >= 41.0.0, < 41.0.4

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JSON

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GHSA-243V-98VX-264H

Vulnerability from github – Published: 2026-02-24 21:08 – Updated: 2026-02-27 20:25

Summary

Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance

Details

Impact

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.

Patches

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.

Workarounds

There are no known workarounds at this time, embedders are encouraged to update to a patched version of Wasmtime.

Resources

Limitations of http::HeaderMap

Severity ?

6.9 (Medium)


                  
                    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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "24.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "25.0.0"
            },
            {
              "fixed": "36.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "37.0.0"
            },
            {
              "fixed": "40.0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27572"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-24T21:08:06Z",
    "nvd_published_at": "2026-02-24T22:16:32Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWasmtime\u0027s implementation of the `wasi:http/types.fields` resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime\u0027s 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)",
  "id": "GHSA-243v-98vx-264h",
  "modified": "2026-02-27T20:25:44Z",
  "published": "2026-02-24T21:08:06Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27572"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a"
    },
    {
      "type": "WEB",
      "url": "https://docs.rs/http/1.4.0/http/header/#limitations"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/bytecodealliance/wasmtime"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0021.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance"
}

cve-2026-27572

Vulnerability from osv_rustsec

Published

2026-02-24 12:00

Modified

2026-02-24 19:42

Summary

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

Details

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.

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [],
        "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",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime",
        "purl": "pkg:cargo/wasmtime"
      },
      "ranges": [
        {
          "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"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2026-27572",
    "GHSA-243v-98vx-264h"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "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.",
  "id": "RUSTSEC-2026-0021",
  "modified": "2026-02-24T19:42:18Z",
  "published": "2026-02-24T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/wasmtime"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0021.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h"
    }
  ],
  "related": [],
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Panic adding excessive fields to a `wasi:http/types.fields` instance"
}

FKIE_CVE-2026-27572

Vulnerability from fkie_nvd - Published: 2026-02-24 22:16 - Updated: 2026-02-25 15:36

Severity ?

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

URL	Tags
security-advisories@github.com	https://docs.rs/http/1.4.0/http/header/#limitations	Not Applicable
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a	Patch
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6	Product, Release Notes
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6	Product, Release Notes
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4	Product, Release Notes
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4	Product, Release Notes
security-advisories@github.com	https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h	Third Party Advisory

Impacted products

Vendor	Product	Version
bytecodealliance	wasmtime	*
bytecodealliance	wasmtime	*
bytecodealliance	wasmtime	*
bytecodealliance	wasmtime	*

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "FAB7C7D9-433F-4046-932B-44456BB034A3",
              "versionEndExcluding": "24.0.6",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "4AF1D021-3AC7-419E-AD0B-5C5738DC51E5",
              "versionEndExcluding": "36.0.6",
              "versionStartIncluding": "25.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "2DBCFCF3-5A70-4441-B73D-E1CE96B01BE7",
              "versionEndExcluding": "40.0.4",
              "versionStartIncluding": "37.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "9BF3C16E-C1D8-468A-9F60-9F6F45DA98E3",
              "versionEndExcluding": "41.0.4",
              "versionStartIncluding": "41.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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\u0027s implementation of the `wasi:http/types.fields` resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime\u0027s 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."
    }
  ],
  "id": "CVE-2026-27572",
  "lastModified": "2026-02-25T15:36:36.380",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-02-24T22:16:32.687",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Not Applicable"
      ],
      "url": "https://docs.rs/http/1.4.0/http/header/#limitations"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Product",
        "Release Notes"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-27572 (GCVE-0-2026-27572)

GHSA-243V-98VX-264H

Impact

Patches

Workarounds

Resources

cve-2026-27572

Vulnerability from osv_rustsec

FKIE_CVE-2026-27572

Tags

Sightings

Nomenclature