Vulnerability-Lookup

CVE-2026-35186 (GCVE-0-2026-35186)

Vulnerability from cvelistv5 – Published: 2026-04-09 18:54 – Updated: 2026-04-13 20:18

Title

Wasmtime has an improperly masked return value from `table.grow` with Winch compiler backend

Summary

Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler backend contains a bug where translating the table.grow operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally in Winch, is tagged as a 64-bit value instead of a 32-bit value. This invalid internal representation of Winch's compiler state compounds into further issues depending on how the value is consumed. The primary consequence of this bug is that bytes in the host's address space can be stored/read from. This is only applicable to the 16 bytes before linear memory, however, as the only significant return value of table.grow that can be misinterpreted is -1. The bytes before linear memory are, by default, unmapped memory. Wasmtime will detect this fault and abort the process, however, because wasm should not be able to access these bytes. Overall this this bug in Winch represents a DoS vector by crashing the host process, a correctness issue within Winch, and a possible leak of up to 16-bytes before linear memory. Wasmtime's default compiler is Cranelift, not Winch, and Wasmtime's default settings are to place guard pages before linear memory. This means that Wasmtime's default configuration is not affected by this issue, and when explicitly choosing Winch Wasmtime's otherwise default configuration leads to a DoS. Disabling guard pages before linear memory is required to possibly leak up to 16-bytes of host data. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.

Severity

6.1 (Medium)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-13 20:17 UTC

CWE

CWE-789 - Memory Allocation with Excessive Size Value

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 8035 records in the last 180 days details

References

1 reference

URL	Tags
https://github.com/bytecodealliance/wasmtime/secu…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version	CPE status
bytecodealliance	wasmtime	Affected: >= 25.0.0, < 36.0.7 Affected: >= 37.0.0, < 42.0.2 Affected: >= 43.0.0, < 44.0.1	guessed

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        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-35186",
        "datePublished": "2026-04-09T18:54:48.760Z",
        "dateReserved": "2026-04-01T17:26:21.134Z",
        "dateUpdated": "2026-04-13T20:18:21.954Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-35186

Vulnerability from fkie_nvd - Published: 2026-04-09 19:16 - Updated: 2026-10-26 22:10

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://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-f984-pcp8-v2p7	Vendor Advisory

Impacted products

Vendor	Product	Version
bytecodealliance	wasmtime	*
bytecodealliance	wasmtime	*
bytecodealliance	wasmtime	43.0.0

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "wasmtime",
          "vendor": "bytecodealliance",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 25.0.0, \u003c 36.0.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 37.0.0, \u003c 42.0.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 43.0.0, \u003c 44.0.1"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "B5AB2157-3977-49F9-9058-6B16A2556170",
              "versionEndExcluding": "36.0.7",
              "versionStartIncluding": "25.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
              "matchCriteriaId": "1D7B70EB-93E3-4732-AB70-E6A531178941",
              "versionEndExcluding": "42.0.2",
              "versionStartIncluding": "37.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:bytecodealliance:wasmtime:43.0.0:*:*:*:*:rust:*:*",
              "matchCriteriaId": "9AD0150A-FE79-4EA6-995B-8CAFC7F246B5",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime\u0027s Winch compiler backend contains a bug where translating the table.grow operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally in Winch, is tagged as a 64-bit value instead of a 32-bit value. This invalid internal representation of Winch\u0027s compiler state compounds into further issues depending on how the value is consumed. The primary consequence of this bug is that bytes in the host\u0027s address space can be stored/read from. This is only applicable to the 16 bytes before linear memory, however, as the only significant return value of table.grow that can be misinterpreted is -1. The bytes before linear memory are, by default, unmapped memory. Wasmtime will detect this fault and abort the process, however, because wasm should not be able to access these bytes. Overall this this bug in Winch represents a DoS vector by crashing the host process, a correctness issue within Winch, and a possible leak of up to 16-bytes before linear memory. Wasmtime\u0027s default compiler is Cranelift, not Winch, and Wasmtime\u0027s default settings are to place guard pages before linear memory. This means that Wasmtime\u0027s default configuration is not affected by this issue, and when explicitly choosing Winch Wasmtime\u0027s otherwise default configuration leads to a DoS. Disabling guard pages before linear memory is required to possibly leak up to 16-bytes of host data. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1."
    },
    {
      "lang": "es",
      "value": "Wasmtime es un entorno de ejecuci\u00f3n para WebAssembly. Desde la versi\u00f3n 25.0.0 hasta antes de las versiones 36.0.7, 42.0.2 y 43.0.1, el backend del compilador Winch de Wasmtime contiene un error donde la traducci\u00f3n del operador table.grow hace que el resultado tenga un tipo incorrecto. Para tablas de 32 bits, esto significa que el resultado del operador, internamente en Winch, se etiqueta como un valor de 64 bits en lugar de un valor de 32 bits. Esta representaci\u00f3n interna inv\u00e1lida del estado del compilador de Winch se agrava en problemas adicionales dependiendo de c\u00f3mo se consume el valor. La consecuencia principal de este error es que se pueden almacenar/leer bytes del espacio de direcciones del host. Esto solo es aplicable a los 16 bytes antes de la memoria lineal, sin embargo, ya que el \u00fanico valor de retorno significativo de table.grow que puede ser malinterpretado es -1. Los bytes antes de la memoria lineal son, por defecto, memoria no mapeada. Wasmtime detectar\u00e1 este fallo y abortar\u00e1 el proceso, sin embargo, porque wasm no deber\u00eda poder acceder a estos bytes. En general, este error en Winch representa un vector de DoS al bloquear el proceso del host, un problema de correcci\u00f3n dentro de Winch y una posible fuga de hasta 16 bytes antes de la memoria lineal. El compilador predeterminado de Wasmtime es Cranelift, no Winch, y la configuraci\u00f3n predeterminada de Wasmtime es colocar p\u00e1ginas de guardia antes de la memoria lineal. Esto significa que la configuraci\u00f3n predeterminada de Wasmtime no se ve afectada por este problema, y al elegir expl\u00edcitamente Winch, la configuraci\u00f3n por defecto de Wasmtime, de lo contrario, conduce a un DoS. Deshabilitar las p\u00e1ginas de guardia antes de la memoria lineal es necesario para posiblemente filtrar hasta 16 bytes de datos del host. Esta vulnerabilidad se corrige en las versiones 36.0.7, 42.0.2 y 43.0.1."
    }
  ],
  "id": "CVE-2026-35186",
  "lastModified": "2026-10-26T22:10:00.163",
  "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": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "HIGH",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.1,
          "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": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "HIGH",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-35186",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-04-13T20:17:58.130808Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-04-09T19:16:25.343",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-f984-pcp8-v2p7"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-789"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-F984-PCP8-V2P7

Vulnerability from github – Published: 2026-04-10 15:32 – Updated: 2026-04-10 15:32

Summary

Wasmtime has improperly masked return value from `table.grow` with Winch compiler backend

Details

Impact

Wasmtime's Winch compiler backend contains a bug where translating the table.grow operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally in Winch, is tagged as a 64-bit value instead of a 32-bit value. This invalid internal representation of Winch's compiler state compounds into further issues depending on how the value is consumed.

One example can be seen when the result of table.grow is used as the address of a load operation. The load operation is tricked into thinking the address is a 64-bit value, not a 32-bit value, which means that the final address to load from is calculated incorrectly. This can lead to a situation where the bytes before the start of linear memory can be loaded/stored to.

The primary consequence of this bug is that bytes in the host's address space can be stored/read from. This is only applicable to the 16 bytes before linear memory, however, as the only significant return value of table.grow that can be misinterpreted is -1. The bytes before linear memory are, by default, unmapped memory. Wasmtime will detect this fault and abort the process, however, because wasm should not be able to access these bytes.

Overall this this bug in Winch represents a DoS vector by crashing the host process, a correctness issue within Winch, and a possible leak of up to 16-bytes before linear memory. Wasmtime's default compiler is Cranelift, not Winch, and Wasmtime's default settings are to place guard pages before linear memory. This means that Wasmtime's default configuration is not affected by this issue, and when explicitly choosing Winch Wasmtime's otherwise default configuration leads to a DoS. Disabling guard pages before linear memory is required to possibly leak up to 16-bytes of host data.

Patches

Wasmtime 43.0.1, 42.0.2, and 36.0.7 have been released with fixes for this issue.

Workaround

There are no workarounds within the Winch compiler backend while using the affected versions. Users of Wasmtime are encouraged either to upgrade to patched versions or, if that is not possible, use the Cranelift compiler backend.

Severity

6.1 (Medium)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "25.0.0"
            },
            {
              "fixed": "36.0.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "37.0.0"
            },
            {
              "fixed": "42.0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "wasmtime"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "43.0.0"
            },
            {
              "fixed": "43.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "43.0.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35186"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-10T15:32:49Z",
    "nvd_published_at": "2026-04-09T19:16:25Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nWasmtime\u0027s Winch compiler backend contains a bug where translating the `table.grow` operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally in Winch, is tagged as a 64-bit value instead of a 32-bit value. This invalid internal representation of Winch\u0027s compiler state compounds into further issues depending on how the value is consumed.\n\nOne example can be seen when the result of `table.grow` is used as the address of a load operation. The load operation is tricked into thinking the address is a 64-bit value, not a 32-bit value, which means that the final address to load from is calculated incorrectly. This can lead to a situation where the bytes before the start of linear memory can be loaded/stored to.\n\nThe primary consequence of this bug is that bytes in the host\u0027s address space can be stored/read from. This is only applicable to the 16 bytes before linear memory, however, as the only significant return value of `table.grow` that can be misinterpreted is -1. The bytes before linear memory are, by default, unmapped memory. Wasmtime will detect this fault and abort the process, however, because wasm should not be able to access these bytes.\n\nOverall this this bug in Winch represents a DoS vector by crashing the host process, a correctness issue within Winch, and a possible leak of up to 16-bytes before linear memory. Wasmtime\u0027s default compiler is Cranelift, not Winch, and Wasmtime\u0027s default settings are to place guard pages before linear memory. This means that Wasmtime\u0027s default configuration is not affected by this issue, and when explicitly choosing Winch Wasmtime\u0027s otherwise default configuration leads to a DoS. Disabling guard pages before linear memory is required to possibly leak up to 16-bytes of host data.\n\n### Patches\n\nWasmtime 43.0.1, 42.0.2, and 36.0.7 have been released with fixes for this issue.\n\n### Workaround\n\nThere are no workarounds within the Winch compiler backend while using the affected versions. Users of Wasmtime are encouraged either to upgrade to patched versions or, if that is not possible, use the Cranelift compiler backend.",
  "id": "GHSA-f984-pcp8-v2p7",
  "modified": "2026-04-10T15:32:49Z",
  "published": "2026-04-10T15:32:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-f984-pcp8-v2p7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35186"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/bytecodealliance/wasmtime"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0094.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Wasmtime has improperly masked return value from `table.grow` with Winch compiler backend"
}

OPENSUSE-SU-2026:10715-1

Vulnerability from csaf_opensuse - Published: 2026-05-06 00:00 - Updated: 2026-09-29 17:30

Summary

libtree-sitter0_26-0.26.8-2.1 on GA media

Severity

Moderate

Scope

4 vulnerabilities in this advisory, including CVE-2026-35186.

CVE-2026-35186

6.4 (Medium)


                
                  CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

Recommended: 16 products

Open the full advisory

OPENSUSE-SU-2026:20749-1

Vulnerability from csaf_opensuse - Published: 2026-05-14 08:07 - Updated: 2026-09-29 17:31

Summary

Security update for tree-sitter

Severity

Important

Scope

10 vulnerabilities in this advisory, including CVE-2026-35186.

CVE-2026-35186

6.4 (Medium)


                
                  CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

Recommended: 13 products

Open the full advisory

RUSTSEC-2026-0094 (CVE-2026-35186)

Vulnerability from osv_rustsec – Published: 2026-04-09 12:00 – Updated: 2026-10-12 17:47 – Source website

Summary

Improperly masked return value from `table.grow` with Winch compiler backend

Details

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-f984-pcp8-v2p7 For more information see the GitHub-hosted security advisory.

Severity

6.1 (Medium)


                    
                      CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

References

URL

Type

	https://crates.io/crates/wasmtime	PACKAGE
	https://rustsec.org/advisories/RUSTSEC-2026-0094.html	ADVISORY
	https://github.com/bytecodealliance/wasmtime/pull/13014	WEB

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [],
        "cvss": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
        "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": "36.0.7"
            },
            {
              "introduced": "37.0.0"
            },
            {
              "fixed": "42.0.2"
            },
            {
              "introduced": "43.0.0"
            },
            {
              "fixed": "43.0.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2026-35186",
    "GHSA-f984-pcp8-v2p7"
  ],
  "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-f984-pcp8-v2p7\nFor more information see the GitHub-hosted security advisory.",
  "id": "RUSTSEC-2026-0094",
  "modified": "2026-10-12T17:47:59Z",
  "published": "2026-04-09T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/wasmtime"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0094.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bytecodealliance/wasmtime/pull/13014"
    }
  ],
  "related": [],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Improperly masked return value from `table.grow` with Winch compiler backend"
}

SUSE-SU-2026:21789-1

Vulnerability from csaf_suse - Published: 2026-05-14 08:09 - Updated: 2026-09-29 17:26

Summary

Security update for tree-sitter

Severity

Important

Scope

10 vulnerabilities in this advisory, including CVE-2026-35186.

CVE-2026-35186

6.4 (Medium)


                
                  CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

Recommended: 18 products

Open the full advisory

UBUNTU-CVE-2026-35186 (CVE-2026-35186)

Vulnerability from osv_ubuntu – Published: 2026-04-09 19:16 – Updated: 2026-10-17 09:40 – Source website

Details

Severity

6.1 (Medium)


                    
                      CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

7.5 (High)


                    
                      CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-35186	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-35186	REPORT
	https://github.com/bytecodealliance/wasmtime/secu…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "librust-cranelift-dev",
            "binary_version": "0.103.0+16.0.0+dfsg-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "rust-wasmtime",
        "purl": "pkg:deb/ubuntu/rust-wasmtime@16.0.0+dfsg-3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "10.0.1+dfsg-7",
        "15.0.1+dfsg-4",
        "16.0.0+dfsg-2",
        "16.0.0+dfsg-3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "librust-cranelift-dev",
            "binary_version": "0.113.1+26.0.1+dfsg-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "rust-wasmtime",
        "purl": "pkg:deb/ubuntu/rust-wasmtime@26.0.1+dfsg-3?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "26.0.1+dfsg-3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "librust-cranelift-dev",
            "binary_version": "0.123.13+36.0.13+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "rust-wasmtime",
        "purl": "pkg:deb/ubuntu/rust-wasmtime@36.0.13+dfsg-1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "36.0.5+dfsg-1",
        "36.0.13+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "librust-cranelift-dev",
            "binary_version": "0.123.5+36.0.5+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "rust-wasmtime",
        "purl": "pkg:deb/ubuntu/rust-wasmtime@36.0.5+dfsg-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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"
      ]
    }
  ],
  "aliases": [],
  "details": "Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime\u0027s Winch compiler backend contains a bug where translating the table.grow operator causes the result to be incorrectly typed. For 32-bit tables this means that the result of the operator, internally in Winch, is tagged as a 64-bit value instead of a 32-bit value. This invalid internal representation of Winch\u0027s compiler state compounds into further issues depending on how the value is consumed. The primary consequence of this bug is that bytes in the host\u0027s address space can be stored/read from. This is only applicable to the 16 bytes before linear memory, however, as the only significant return value of table.grow that can be misinterpreted is -1. The bytes before linear memory are, by default, unmapped memory. Wasmtime will detect this fault and abort the process, however, because wasm should not be able to access these bytes. Overall this this bug in Winch represents a DoS vector by crashing the host process, a correctness issue within Winch, and a possible leak of up to 16-bytes before linear memory. Wasmtime\u0027s default compiler is Cranelift, not Winch, and Wasmtime\u0027s default settings are to place guard pages before linear memory. This means that Wasmtime\u0027s default configuration is not affected by this issue, and when explicitly choosing Winch Wasmtime\u0027s otherwise default configuration leads to a DoS. Disabling guard pages before linear memory is required to possibly leak up to 16-bytes of host data. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.",
  "id": "UBUNTU-CVE-2026-35186",
  "modified": "2026-10-17T09:40:53Z",
  "published": "2026-04-09T19:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-35186"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-35186"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-f984-pcp8-v2p7"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-35186"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-35186 (GCVE-0-2026-35186)

FKIE_CVE-2026-35186

GHSA-F984-PCP8-V2P7

Impact

Patches

Workaround

OPENSUSE-SU-2026:10715-1

OPENSUSE-SU-2026:20749-1

RUSTSEC-2026-0094 (CVE-2026-35186)

SUSE-SU-2026:21789-1

UBUNTU-CVE-2026-35186 (CVE-2026-35186)

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Related by attack behaviour