Vulnerabilities in pkg:npm/smol-toml

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r4xh-jqrq-34v2",
  "modified" : "2026-10-05T23:41:14Z",
  "published" : "2026-10-05T23:41:14Z",
  "aliases" : [ ],
  "summary" : "smol-toml: Quadratic-time parse() from parseKey rescanning to end of document on each key line",
  "details" : "### Summary\n\n`parse()` has a quadratic-time path in `parseKey`, reachable on default options with ordinary valid input. For every key line and table-header line, `parseKey` (dist/struct.js, lines 58 and 86) finds the dotted-key separator with `ctx.s.indexOf('.', ctx.p)`, where `ctx.s` is the whole document. When a key has no `.` ahead of it, that search runs all the way to the end of the input, and the result is then clamped back to the line terminator `endPtr` - so everything scanned past the current line is wasted. `parseKey` runs once per line, so a document of N dot-free keys costs O(n^2).\n\nThe most ordinary TOML shape triggers it: a flat list of `key = value` lines, or a repeated `[[a]]` table. No dotted keys, no special options, valid input throughout.\n\n### Proof of concept\n\n```js\nimport { parse } from 'smol-toml'\n\nlet doc = ''\nfor (let i = 0; i < 256000; i++) doc += 'k' + i + ' = 1\\n'\n\nconsole.time('parse')\nparse(doc) // ~2.8 MB of valid TOML, default options\nconsole.timeEnd('parse')\n```\n\nDoubling the line count roughly quadruples the time:\n\n| lines | size | parse() |\n|---|---|---|\n| 32k | 0.3 MB | 0.3 s |\n| 64k | 0.7 MB | 1.0 s |\n| 128k | 1.4 MB | 3.5 s |\n| 256k | 2.8 MB | 14 s |\n\n### Impact\nAny service that runs `parse()` on attacker-supplied TOML can be stalled. The work is synchronous, so it blocks the whole event loop, and the quadratic is unbounded: a ~7 MB body pins a core for about a minute, larger bodies for several.\n\n### Patches\nVersion 1.9.0 uses a different implementation for parsing keys which is strictly linear.\n\n### Workarounds\nLimit the maximum document size accepted when parsing arbitrary documents.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "smol-toml"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.9.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.8.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/squirrelchat/smol-toml/security/advisories/GHSA-r4xh-jqrq-34v2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/squirrelchat/smol-toml/commit/99102aa57fc932f760ea9c15b4cf1c181f952d24"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/squirrelchat/smol-toml"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/squirrelchat/smol-toml/releases/tag/v1.9.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-407" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-05T23:41:14Z",
    "nvd_published_at" : null
  }
}