GHSA-MWMH-MQ4G-G6GR

Vulnerability from github – Published: 2026-04-03 02:41 – Updated: 2026-04-06 23:10
VLAI
Summary
Electron: Registry key path injection in app.setAsDefaultProtocolClient on Windows
Details

Impact

On Windows, app.setAsDefaultProtocolClient(protocol) did not validate the protocol name before writing to the registry. Apps that pass untrusted input as the protocol name may allow an attacker to write to arbitrary subkeys under HKCU\Software\Classes\, potentially hijacking existing protocol handlers.

Apps are only affected if they call app.setAsDefaultProtocolClient() with a protocol name derived from external or untrusted input. Apps that use a hardcoded protocol name are not affected.

Workarounds

Validate the protocol name matches /^[a-zA-Z][a-zA-Z0-9+.-]*$/ before passing it to app.setAsDefaultProtocolClient().

Fixed Versions

  • 41.0.0
  • 40.8.1
  • 39.8.1
  • 38.8.6

For more information

If there are any questions or comments about this advisory, please email security@electronjs.org

Severity
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "electron"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "38.8.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "electron"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "39.0.0-alpha.1"
            },
            {
              "fixed": "39.8.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "electron"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "40.0.0-alpha.1"
            },
            {
              "fixed": "40.8.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "electron"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "41.0.0-alpha.1"
            },
            {
              "fixed": "41.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34773"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-74"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-03T02:41:52Z",
    "nvd_published_at": "2026-04-04T00:16:18Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\nOn Windows, `app.setAsDefaultProtocolClient(protocol)` did not validate the protocol name before writing to the registry. Apps that pass untrusted input as the protocol name may allow an attacker to write to arbitrary subkeys under `HKCU\\Software\\Classes\\`, potentially hijacking existing protocol handlers.\n\nApps are only affected if they call `app.setAsDefaultProtocolClient()` with a protocol name derived from external or untrusted input. Apps that use a hardcoded protocol name are not affected.\n\n### Workarounds\nValidate the protocol name matches `/^[a-zA-Z][a-zA-Z0-9+.-]*$/` before passing it to `app.setAsDefaultProtocolClient()`.\n\n### Fixed Versions\n* `41.0.0`\n* `40.8.1`\n* `39.8.1`\n* `38.8.6`\n\n### For more information\nIf there are any questions or comments about this advisory, please email [security@electronjs.org](mailto:security@electronjs.org)",
  "id": "GHSA-mwmh-mq4g-g6gr",
  "modified": "2026-04-06T23:10:51Z",
  "published": "2026-04-03T02:41:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/electron/electron/security/advisories/GHSA-mwmh-mq4g-g6gr"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34773"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/electron/electron"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Electron: Registry key path injection in app.setAsDefaultProtocolClient on Windows"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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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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