GHSA-4X5R-PXFX-6JF8

Vulnerability from github – Published: 2026-06-15 17:14 – Updated: 2026-06-15 17:14
VLAI
Summary
@babel/core: Arbitrary File Read via sourceMappingURL Comment
Details

Impact

Using @babel/core to compile maliciously crafted code can allow ab attacker to read any source map from the system that is running Babel, if these conditions are all true: - the attacker controls the input source code - the attacker can read the output source code - the attacker knows the path of the source map file that they want to read

Users that only compile trusted code are not impacted.

Patches

The vulnerability has been fixed in @babel/core@7.29.6 and @babel/core@8.0.0-rc.6.

Workarounds

Callers can mitigate the issue without upgrading by setting inputSourceMap: false in their Babel options.

Callers can also manually extract the #sourceMappingURL comment from the input source code, validate whether the source map that it links to is allowed to be read, and if it is pass an object to inputSourceMap (passing false when it's not).

Credits

Thanks Teodor-Cristian Radoi for reporting the vulnerability.

Severity
3.2 (Low)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 8.0.0-rc.5"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@babel/core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0-alpha.0"
            },
            {
              "fixed": "8.0.0-rc.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 7.29.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@babel/core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.29.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-49356"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-15T17:14:14Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "## Impact\n\nUsing `@babel/core` to compile maliciously crafted code can allow ab attacker to read any source map from the system that is running Babel, if these conditions are _all_ true:\n- the attacker controls the input source code\n- the attacker can read the output source code\n- the attacker knows the path of the source map file that they want to read\n\n**Users that only compile trusted code are not impacted.**\n\n## Patches\n\nThe vulnerability has been fixed in `@babel/core@7.29.6` and `@babel/core@8.0.0-rc.6`.\n\n## Workarounds\n\nCallers can mitigate the issue without upgrading by setting [`inputSourceMap: false`](https://babeljs.io/docs/options#inputsourcemap) in their Babel options.\n\nCallers can also manually extract the `#sourceMappingURL` comment from the input source code, validate whether the source map that it links to is allowed to be read, and if it is pass an object to `inputSourceMap` (passing `false` when it\u0027s not).\n\n## Credits\n\nThanks Teodor-Cristian Radoi for reporting the vulnerability.",
  "id": "GHSA-4x5r-pxfx-6jf8",
  "modified": "2026-06-15T17:14:14Z",
  "published": "2026-06-15T17:14:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/babel/babel/security/advisories/GHSA-4x5r-pxfx-6jf8"
    },
    {
      "type": "WEB",
      "url": "https://babeljs.io/docs/options#inputsourcemap"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/babel/babel"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "@babel/core: Arbitrary File Read via sourceMappingURL Comment"
}


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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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