GHSA-8VCH-M3F4-Q8JF

Vulnerability from github – Published: 2025-12-09 17:12 – Updated: 2025-12-09 21:37
VLAI?
Summary
Elysia affected by arbitrary code injection through cookie config
Details

Arbitrary code execution from cookie config. If dynamic cookies are enabled (ie there exists a schema for cookies), the cookie config is injected into the compiled route without first being sanitised.

Availability of this exploit is generally low, as it requires write access to either the Elysia app's source code (in which case the vulnerability is meaningless) or write access to the cookie config (perhaps where it is assumed to be provisioned by the environment).

However when combined with GHSA-hxj9-33pp-j2cc, this vulnerability allows for a full RCE chain.

Impact

  • aot enabled (default)
  • cookie schema passed to route
  • Cookie config controllable eg. via env

Example of vulnerable code

new Elysia({
    cookie: {
        secrets: `' + console.log('pwned from secrets') + '`
    },
})
    .get("/", () => "hello world", {
        cookie: t.Cookie({
            foo: t.Any(),
        }),
    })

POC: https://github.com/sportshead/elysia-poc

Patches

Patched by 1.4.17 (https://github.com/elysiajs/elysia/pull/1564)

Reference commit: - https://github.com/elysiajs/elysia/pull/1564/commits/26935bf76ebc43b4a43d48b173fc853de43bb51e - https://github.com/elysiajs/elysia/pull/1564/commits/3af978663e437dccc6c1a2a3aff4b74e1574849e

Workarounds

Sanitize cookie-related env input

const overrideUnsafeQuote = (value: string) =>
    // '`' + value + '`'
    '`' + value.replace(/'/g, '\\`').replace(/\${/g, '$\\{') + '`'
Severity ?
7.5 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "elysia"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.4.18"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-66457"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-09T17:12:05Z",
    "nvd_published_at": "2025-12-09T20:15:54Z",
    "severity": "HIGH"
  },
  "details": "Arbitrary code execution from cookie config. If dynamic cookies are enabled (ie there exists a schema for cookies), the cookie config is injected into the compiled route without first being sanitised.\n\nAvailability of this exploit is generally low, as it requires write access to either the Elysia app\u0027s source code (in which case the vulnerability is meaningless) or write access to the cookie config (perhaps where it is assumed to be provisioned by the environment). \n\nHowever when combined with GHSA-hxj9-33pp-j2cc, this vulnerability allows for a full RCE chain.\n\n### Impact\n- aot enabled (default)\n- cookie schema passed to route\n- Cookie config controllable eg. via env\n\nExample of vulnerable code\n```js\nnew Elysia({\n\tcookie: {\n\t\tsecrets: `\u0027 + console.log(\u0027pwned from secrets\u0027) + \u0027`\n\t},\n})\n\t.get(\"/\", () =\u003e \"hello world\", {\n\t\tcookie: t.Cookie({\n\t\t\tfoo: t.Any(),\n\t\t}),\n\t})\n```\n\nPOC: https://github.com/sportshead/elysia-poc\n\n### Patches\nPatched by 1.4.17 (https://github.com/elysiajs/elysia/pull/1564)\n\nReference commit:\n- https://github.com/elysiajs/elysia/pull/1564/commits/26935bf76ebc43b4a43d48b173fc853de43bb51e\n- https://github.com/elysiajs/elysia/pull/1564/commits/3af978663e437dccc6c1a2a3aff4b74e1574849e\n\n### Workarounds\nSanitize cookie-related env input\n\n```typescript\nconst overrideUnsafeQuote = (value: string) =\u003e\n\t// \u0027`\u0027 + value + \u0027`\u0027\n\t\u0027`\u0027 + value.replace(/\u0027/g, \u0027\\\\`\u0027).replace(/\\${/g, \u0027$\\\\{\u0027) + \u0027`\u0027\n```",
  "id": "GHSA-8vch-m3f4-q8jf",
  "modified": "2025-12-09T21:37:17Z",
  "published": "2025-12-09T17:12:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/security/advisories/GHSA-8vch-m3f4-q8jf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/security/advisories/GHSA-hxj9-33pp-j2cc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66457"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/pull/1564"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/commit/26935bf76ebc43b4a43d48b173fc853de43bb51e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/elysiajs/elysia/commit/3af978663e437dccc6c1a2a3aff4b74e1574849e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/elysiajs/elysia"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sportshead/elysia-poc"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Elysia affected by arbitrary code injection through cookie config"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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