GHSA-Q4X5-8CJ6-52WG

Vulnerability from github – Published: 2026-06-05 16:34 – Updated: 2026-07-08 17:36
VLAI
Summary
Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP
Details

Summary: The private IP blocklist regex used in the URL download feature does not match IPv4-mapped IPv6 addresses (e.g. ::ffff:127.0.0.1), allowing SSRF protection to be bypassed on dual-stack systems.

Affected components

backend/src/applications/files/services/files-manager.service.ts – downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress. backend/src/applications/files/utils/url-file.ts – regExpPrivateIP does not include ::ffff: variants.

Details: The regExpPrivateIP regex in backend/src/applications/files/utils/url-file.ts correctly blocks standard IPv4 private ranges but does not include ::ffff: prefixed variants. On dual-stack systems, Node.js can report a socket's remoteAddress in IPv4-mapped IPv6 form, meaning the check in FilesManager.downloadFromUrl() can be bypassed entirely.

PoC: poc.pdf

Proof: 1000226655

Impact: An attacker can supply a crafted URL pointing to an internal address that gets reported as ::ffff:127.0.0.1 or ::ffff:10.x.x.x, causing the server to fetch internal resources that should be blocked. Any user with access to the file download feature is a potential attacker.

Severity
7.7 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.2.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@sync-in/server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-47684"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-05T16:34:59Z",
    "nvd_published_at": "2026-06-16T15:16:41Z",
    "severity": "HIGH"
  },
  "details": "Summary:\nThe private IP blocklist regex used in the URL download feature does not match IPv4-mapped IPv6 addresses (e.g. ::ffff:127.0.0.1), allowing SSRF protection to be bypassed on dual-stack systems.\n\nAffected components\n\nbackend/src/applications/files/services/files-manager.service.ts \u2013 downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress.\nbackend/src/applications/files/utils/url-file.ts \u2013 regExpPrivateIP does not include ::ffff:\u003cipv4\u003e variants.\n\nDetails:\nThe regExpPrivateIP regex in backend/src/applications/files/utils/url-file.ts correctly blocks standard IPv4 private ranges but does not include ::ffff: prefixed variants. On dual-stack systems, Node.js can report a socket\u0027s remoteAddress in IPv4-mapped IPv6 form, meaning the check in FilesManager.downloadFromUrl() can be bypassed entirely.\n\nPoC:\n[poc.pdf](https://github.com/user-attachments/files/26990874/poc.pdf)\n\n\n\n\nProof:\n\u003cimg width=\"1080\" height=\"842\" alt=\"1000226655\" src=\"https://github.com/user-attachments/assets/797cea83-0a08-4a16-a91b-31c51068d473\" /\u003e\n\n\n\n\n\nImpact:\nAn attacker can supply a crafted URL pointing to an internal address that gets reported as ::ffff:127.0.0.1 or ::ffff:10.x.x.x, causing the server to fetch internal resources that should be blocked. Any user with access to the file download feature is a potential attacker.",
  "id": "GHSA-q4x5-8cj6-52wg",
  "modified": "2026-07-08T17:36:17Z",
  "published": "2026-06-05T16:34:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Sync-in/server/security/advisories/GHSA-q4x5-8cj6-52wg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-47684"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Sync-in/server"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Sync-in/server/releases/tag/v2.3.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP"
}



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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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