GHSA-VM9P-MX69-HF3F

Vulnerability from github – Published: 2026-07-01 21:36 – Updated: 2026-07-01 21:36
VLAI
Details

Ladybird contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop iteration ends the FunctionType is destroyed, leaving the callback with a dangling reference (the normal instantiate path uses a long-lived reference and is not affected). Stale result-type data lets the host callback return an empty result vector for a statically non-empty result, so the destination register retains an attacker-influenced value that is then consumed by the WASM-GC array.set handler, which bit-casts the reference low bits to an ArrayInstance pointer after only a null check, yielding an arbitrary write. A web page can chain this into code execution in the WebContent process. Verified reachable from HTML content without any instrumentation or source modification.

Severity
8.3 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
8.9 (High)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-58592"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-01T20:17:11Z",
    "severity": "HIGH"
  },
  "details": "Ladybird contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop iteration ends the FunctionType is destroyed, leaving the callback with a dangling reference (the normal instantiate path uses a long-lived reference and is not affected). Stale result-type data lets the host callback return an empty result vector for a statically non-empty result, so the destination register retains an attacker-influenced value that is then consumed by the WASM-GC array.set handler, which bit-casts the reference low bits to an ArrayInstance pointer after only a null check, yielding an arbitrary write. A web page can chain this into code execution in the WebContent process. Verified reachable from HTML content without any instrumentation or source modification.",
  "id": "GHSA-vm9p-mx69-hf3f",
  "modified": "2026-07-01T21:36:20Z",
  "published": "2026-07-01T21:36:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58592"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LadybirdBrowser/ladybird/blob/master/Libraries/LibWeb/WebAssembly/WebAssemblyModule.cpp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/bikini/exploitarium/tree/main/ladybird-wasm-esm-host-function-rce-poc"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/ladybird-web-reachable-code-execution-via-dangling-functiontype-reference-in-webassembly-esm-integration"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/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",
      "type": "CVSS_V4"
    }
  ]
}


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