CVE-2026-54913 (GCVE-0-2026-54913)

Vulnerability from cvelistv5 – Published: 2026-11-05 17:28 – Updated: 2026-11-05 17:28
VLAI
Title
WebAssembly Micro Runtime: Missing `ref.null` heap-type validation in `load_init_expr` leaks host stack memory to the WebAssembly guest
Summary
WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, load_init_expr in core/iwasm/interpreter/wasm_loader.c accepts a non-reference heap-type byte for ref.null when WASM_ENABLE_GC=0, while the local WASMValue cur_value union is not zero-initialized and setting ref_index writes only part of it. A crafted module can declare an i64, f64, or v128 global initialized through the invalid ref.null form, causing push_const_expr_stack and the later global initialization path to copy uninitialized host-stack bytes into a value readable by the guest. The classic and fast interpreters are affected in the default no-GC configuration; the GC-enabled path validates heap types. The disclosure is four bytes for i64 or f64 globals and up to twelve bytes for each v128 global. This issue is fixed in version 2.4.5.
Severity
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-457 - Use of Uninitialized Variable
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7834 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
bytecodealliance wasm-micro-runtime Affected: < 2.4.5
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "wasm-micro-runtime",
          "vendor": "bytecodealliance",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.4.5"
            }
          ]
        }
      ],
      "descriptions": [
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          "lang": "en",
          "value": "WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, load_init_expr in core/iwasm/interpreter/wasm_loader.c accepts a non-reference heap-type byte for ref.null when WASM_ENABLE_GC=0, while the local WASMValue cur_value union is not zero-initialized and setting ref_index writes only part of it. A crafted module can declare an i64, f64, or v128 global initialized through the invalid ref.null form, causing push_const_expr_stack and the later global initialization path to copy uninitialized host-stack bytes into a value readable by the guest. The classic and fast interpreters are affected in the default no-GC configuration; the GC-enabled path validates heap types. The disclosure is four bytes for i64 or f64 globals and up to twelve bytes for each v128 global. This issue is fixed in version 2.4.5."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
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            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
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              "description": "CWE-457: Use of Uninitialized Variable",
              "lang": "en",
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            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-05T17:28:26.923Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-frwm-5hpr-2hq2",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-frwm-5hpr-2hq2"
        },
        {
          "name": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/c313279c548c6a93f55eb97455cab8696e39f6c1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/c313279c548c6a93f55eb97455cab8696e39f6c1"
        },
        {
          "name": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/e571797fbdf498d9ac4edb495205ea0f01370091",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/e571797fbdf498d9ac4edb495205ea0f01370091"
        },
        {
          "name": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5"
        }
      ],
      "source": {
        "advisory": "GHSA-frwm-5hpr-2hq2",
        "discovery": "UNKNOWN"
      },
      "title": "WebAssembly Micro Runtime: Missing `ref.null` heap-type validation in `load_init_expr` leaks host stack memory to the WebAssembly guest"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-54913",
    "datePublished": "2026-11-05T17:28:26.923Z",
    "dateReserved": "2026-06-16T13:49:33.556Z",
    "dateUpdated": "2026-11-05T17:28:26.923Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-54913",
      "date": "2026-11-09",
      "epss": "0.00301",
      "percentile": "0.23035"
    },
    "nvd": {
      "cve": {
        "affected": [
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            "affectedData": [
              {
                "product": "wasm-micro-runtime",
                "vendor": "bytecodealliance",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 2.4.5"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, load_init_expr in core/iwasm/interpreter/wasm_loader.c accepts a non-reference heap-type byte for ref.null when WASM_ENABLE_GC=0, while the local WASMValue cur_value union is not zero-initialized and setting ref_index writes only part of it. A crafted module can declare an i64, f64, or v128 global initialized through the invalid ref.null form, causing push_const_expr_stack and the later global initialization path to copy uninitialized host-stack bytes into a value readable by the guest. The classic and fast interpreters are affected in the default no-GC configuration; the GC-enabled path validates heap types. The disclosure is four bytes for i64 or f64 globals and up to twelve bytes for each v128 global. This issue is fixed in version 2.4.5."
          }
        ],
        "id": "CVE-2026-54913",
        "lastModified": "2026-11-05T18:17:08.703",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "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": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/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": "NONE",
                "vulnConfidentialityImpact": "LOW",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
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              "type": "Secondary"
            }
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        "references": [
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            "source": "security-advisories@github.com",
            "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/c313279c548c6a93f55eb97455cab8696e39f6c1"
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          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-frwm-5hpr-2hq2"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
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            "description": [
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                "lang": "en",
                "value": "CWE-457"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}



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