eef-cve-2026-115700

{
  "affected": [
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-115700.json"
      },
      "package": {
        "ecosystem": "Hex",
        "name": "hackney",
        "purl": "pkg:hex/hackney"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.1"
            },
            {
              "fixed": "4.9.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": [
        "4.0.1",
        "4.0.2",
        "4.0.3",
        "4.1.0",
        "4.2.0",
        "4.2.1",
        "4.2.2",
        "4.2.3",
        "4.3.0",
        "4.4.0",
        "4.4.1",
        "4.4.2",
        "4.4.3",
        "4.4.5",
        "4.5.0",
        "4.5.1",
        "4.5.2",
        "4.6.0",
        "4.6.1",
        "4.7.0",
        "4.7.1",
        "4.7.2",
        "4.7.3",
        "4.7.4",
        "4.8.0",
        "4.8.1",
        "4.8.2",
        "4.8.3",
        "4.8.4",
        "4.8.5",
        "4.8.6",
        "4.8.7"
      ]
    },
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-115700.json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "452620a92ec1da2e6b4862a049a2a4f04b42068f"
            },
            {
              "fixed": "f19561a0b422376348c91537e51377ab7325f4ee"
            }
          ],
          "repo": "https://github.com/benoitc/hackney",
          "type": "GIT"
        }
      ],
      "versions": [
        "4.8.7",
        "4.8.6",
        "4.8.5",
        "4.8.4",
        "4.8.3",
        "4.8.2",
        "4.8.1",
        "4.8.0",
        "4.7.4",
        "4.7.3",
        "4.7.2",
        "4.7.1",
        "4.7.0",
        "4.6.1",
        "4.6.0",
        "4.5.2",
        "4.5.1",
        "4.5.0",
        "4.4.5",
        "4.4.4",
        "4.4.3",
        "4.4.2",
        "4.4.1",
        "4.4.0",
        "4.3.0",
        "4.2.3",
        "4.2.2",
        "4.2.1",
        "4.2.0",
        "4.1.0",
        "4.0.3",
        "4.0.2",
        "4.0.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-115700"
  ],
  "credits": [
    {
      "name": "Eurico Nicacio",
      "type": "FINDER"
    },
    {
      "name": "Eurico Nicacio",
      "type": "REPORTER"
    },
    {
      "name": "Benoit Chesneau",
      "type": "REMEDIATION_DEVELOPER"
    },
    {
      "name": "Jonatan Männchen / EEF",
      "type": "COORDINATOR"
    }
  ],
  "database_specific": {
    "capec_ids": [
      "CAPEC-664"
    ],
    "cpe_ids": [
      "cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"
    ],
    "cwe_ids": [
      "CWE-436",
      "CWE-918"
    ]
  },
  "details": "## Summary\n\nInterpretation Conflict vulnerability in `hackney_url` in benoitc hackney allows Server Side Request Forgery via a percent-encoded bracketed IPv6 literal or an IP literal with a trailing dot. A host such as `%5B%3A%3Affff%3A127%2E0%2E0%2E1%5D` (decoding to `[::ffff:127.0.0.1]`) or `127.0.0.1.` is not an IP address to a caller's allowlist built on `uri_string:parse/1` and `inet:parse_address/1`, while hackney connects to the address it denotes. The same applies to a `Location` target when redirects are followed.\n\nThe IP-literal gate that `hackney_url:normalize/2` applies to a percent-decoded host, added to close the percent-encoded IP bypass of CVE-2026-47076, passes the decoded value to `inet_parse:address/1` as is. The connect path in `hackney_happy:parse_address/1` drops a surrounding bracket pair, and the resolver ignores a trailing dot, so both forms pass the gate and still reach the literal address. Domain names with a trailing dot and unencoded IPv6 literals are not affected.\n\nThis issue affects hackney: from 4.0.1 before 4.9.0.\n\n## Details\n\n**1. The gate.** `hackney_url:normalize/2` in `src/hackney_url.erl` percent-decodes a host that is not already an IP literal and raises `invalid_url_host` when `inet_parse:address/1` accepts the decoded value. This closed the plain percent-encoded IP case.\n\n**2. What the connect path accepts.** `hackney_happy:parse_address/1` removes a surrounding `[...]` pair before calling `inet:parse_address/1`, and the resolver treats a trailing dot as the root label. Neither form is accepted by `inet_parse:address/1`, so `[::ffff:127.0.0.1]` and `127.0.0.1.` pass the gate.\n\n**3. Result.** A percent-encoded bracketed IPv6 literal such as `%5B%3A%3Affff%3A127%2E0%2E0%2E1%5D`, or an IPv4 literal with a trailing dot, is not an IP address to a caller's check based on `uri_string:parse/1` and `inet:parse_address/1`, but hackney connects to the address it denotes. The same applies to a `Location` target when redirects are followed. The fix strips one bracket pair and one trailing dot in `ip_candidate/1` before the gate.\n\n## Impact\n\nAn application that checks user-supplied URLs against an IP allowlist before handing them to hackney can be made to request loopback, link-local metadata and private-network addresses that the allowlist rejects when they are written plainly.\n\n## Workarounds\n\nRun the allowlist on the host that `hackney_url:normalize/1` returns for the parsed URL, and strip a surrounding bracket pair and a trailing dot from it before the IP check, so the check sees the same address the connect path uses.\n\n## Configurations\n\nThe application passes URLs that an untrusted party can influence to hackney and relies on its own host allowlist, built on `uri_string:parse/1` or `inet:parse_address/1`, to keep requests away from internal addresses.",
  "id": "EEF-CVE-2026-115700",
  "modified": "2026-10-26T14:00:04.842678043Z",
  "published": "2026-10-26T13:49:02.744Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/benoitc/hackney/releases/tag/4.9.0"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-115700.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/benoitc/hackney/pull/987"
    },
    {
      "type": "WEB",
      "url": "https://github.com/benoitc/hackney/commit/452620a92ec1da2e6b4862a049a2a4f04b42068f"
    },
    {
      "type": "FIX",
      "url": "https://github.com/benoitc/hackney/commit/f19561a0b422376348c91537e51377ab7325f4ee"
    },
    {
      "type": "PACKAGE",
      "url": "https://hex.pm/packages/hackney"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "SSRF allowlist bypass via percent-encoded bracketed IPv6 or trailing-dot IP literal in hackney"
}