{
  "schema_version": "1.4.0",
  "id": "GHSA-64fm-8hw2-v72w",
  "modified": "2024-03-25T22:31:55Z",
  "published": "2024-03-25T19:38:18Z",
  "aliases": [
    "CVE-2024-28243"
  ],
  "summary": "KaTeX's maxExpand bypassed by `\\edef`",
  "details": "### Impact\nKaTeX users who render untrusted mathematical expressions could encounter malicious input using `\\edef` that causes a near-infinite loop, despite setting `maxExpand` to avoid such loops. This can be used as an availability attack, where e.g. a client rendering another user's KaTeX input will be unable to use the site due to memory overflow, tying up the main thread, or stack overflow.\n\n### Patches\nUpgrade to KaTeX v0.16.10 to remove this vulnerability.\n\n### Workarounds\nForbid inputs containing the substring `\"\\\\edef\"` before passing them to KaTeX.\n(There is no easy workaround for the auto-render extension.)\n\n### Details\nKaTeX supports an option named `maxExpand` which prevents infinitely recursive macros from consuming all available memory and/or triggering a stack overflow error. However, what counted as an \"expansion\" is a single macro expanding to any number of tokens. The expand-and-define TeX command `\\edef` can be used to build up an exponential number of tokens using only a linear number of expansions according to this definition, e.g. by repeatedly doubling the previous definition. This has been corrected in KaTeX v0.16.10, where every expanded token in an `\\edef` counts as an expansion.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue or security advisory in the [KaTeX repository](https://github.com/KaTeX/KaTeX/)\n* Email us at [katex-security@mit.edu](mailto:katex-security@mit.edu)",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "katex"
      },
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0.10.0-beta"
            },
            {
              "fixed": "0.16.10"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/KaTeX/KaTeX/security/advisories/GHSA-64fm-8hw2-v72w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-28243"
    },
    {
      "type": "WEB",
      "url": "https://github.com/KaTeX/KaTeX/commit/e88b4c357f978b1bca8edfe3297f0aa309bcbe34"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/KaTeX/KaTeX"
    }
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-606",
      "CWE-674"
    ],
    "severity": "MODERATE",
    "github_reviewed": true,
    "github_reviewed_at": "2024-03-25T19:38:18Z",
    "nvd_published_at": "2024-03-25T20:15:07Z"
  }
}