GHSA-9643-4QGH-G8MX

Vulnerability from github – Published: 2026-09-23 21:54 – Updated: 2026-09-23 21:54
VLAI
Summary
elysia has Inefficient Algorithmic Complexity and Interpretation Conflict
Details

Elysia v1.4.28 is vulnerable to denial-of-service attacks due to CPU exhaustion in the form data normalization code.

Elysia uses getAll to retrieve value from FormData. It is called directly relative to the total number of key-value pairs in the form data. The total amount of work the for loop has to do grows quadratically, so doubling the number of unique key-value pairs quadruples the amount of work. In the above PoC, each .getAll call scans through all of the n key-value pairs in the form data. Because there are n unique keys in the form data, there are .getAll calls, so in total the form data normalizer has to scan n x n key-value pairs.

Impact

Endpoints using multipart/form-data

Patches

1.4.29

Workarounds

no 100% confirm workaround beside updating the patch

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "elysia"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.4.29"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56669"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-407",
      "CWE-436"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-23T21:54:50Z",
    "nvd_published_at": "2026-07-08T21:16:50Z",
    "severity": "HIGH"
  },
  "details": "Elysia v1.4.28 is vulnerable to denial-of-service attacks due to CPU exhaustion in the form data normalization code.\n\nElysia uses `getAll` to retrieve value from FormData. It is called directly relative to the total number of key-value pairs in the form data. The total amount of work the for loop has to do grows quadratically, so doubling the number of unique key-value pairs quadruples the amount of work. In the above PoC, each .getAll call scans through all of the `n` key-value pairs in the form data. Because there are `n` unique keys in the form data, there are .getAll calls, so in total the form data normalizer has to scan `n` x `n` key-value pairs.\n\n### Impact\nEndpoints using `multipart/form-data`\n\n### Patches\n1.4.29\n\n### Workarounds\nno 100% confirm workaround beside updating the patch",
  "id": "GHSA-9643-4qgh-g8mx",
  "modified": "2026-09-23T21:54:50Z",
  "published": "2026-09-23T21:54:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/security/advisories/GHSA-9643-4qgh-g8mx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56669"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/commit/8358ff9efbcedf9534995f5977f26b9ceab59329"
    },
    {
      "type": "WEB",
      "url": "https://gist.github.com/jviide/ea040eabe7bac058326174e2cd42dfd9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elysiajs/elysia"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/releases/tag/1.4.29"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "elysia has Inefficient Algorithmic Complexity and Interpretation Conflict"
}



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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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