{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "ratex-parser"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.1.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53531"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-07T23:39:30Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n\nRaTeX\u2019s recursive-descent parser recurses one (or more) native stack frame per nesting level at `{`, `\\left`, `\\sqrt{`, `^{`, etc, with **no maximum depth limit**. A short, ~10 KB input of nested groups overflows the 8 MB main-thread stack and aborts the process. With `panic = \"abort\"` (`Cargo.toml:48`), and because a Rust stack overflow is always a fatal `SIGABRT` regardless of panic strategy this is an unrecoverable, whole-process denial of service reachable from a single untrusted LaTeX string.\n\n### Details\n\nThe mutual recursion has no depth guard (`crates/ratex-parser/src/parser.rs`):\n\n```\nparse_expression (:113)  -\u003e  parse_atom (:281/285)  -\u003e  parse_group (:451)\n                                  ^                          |\n                                  |   on \u0027{\u0027 (:459) recurse  |\n                                  +--------------------------+\n```\n\n`\\left` adds another recursive edge: `handle_left` \u2192 `parse_expression` (`crates/ratex-parser/src/functions/left_right.rs:47`). The only counters present are unrelated to depth: `leftright_depth` (a `\\right`-matching counter, `parser.rs:24`) and the macro expander\u2019s `max_expand = 1000` (`macro_expander.rs:64`), which does **not** gate brace / `\\left` recursion (those tokens never pass through `expand_once`). There is no `recursion_limit`/depth parameter on `parse_group`, `parse_expression`, or `parse_atom`.\n\n### PoC\n\n\u003cimg width=\"1097\" height=\"158\" alt=\"image\" src=\"https://github.com/user-attachments/assets/29b837a2-c455-4cb6-a055-514b31c999c6\" /\u003e\n\n\n```\n$ python3 -c \u0027import sys;sys.stdout.write(\"{\"*200000+\"x\"+\"}\"*200000)\u0027 | ./target/release/parse\nthread \u0027main\u0027 has overflowed its stack\nfatal runtime error: stack overflow, aborting\nAborted (core dumped)            # exit 134\n```\n\n(Other nesting forms work equally, e.g. `\\left(`\u00d7N, `\\sqrt{`\u00d7N, `^{`\u00d7N.)\n\n### Impact\n\nA single small request crashes the whole RaTeX process. In a typical server-side math-rendering service this is a reliable, unauthenticated DoS; on smaller worker-thread stacks (e.g. a 512 KB async runtime thread) only a few hundred bytes of nesting are required.",
  "id": "GHSA-4w5h-hx6r-28q7",
  "modified": "2026-07-07T23:39:30Z",
  "published": "2026-07-07T23:39:30Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/erweixin/RaTeX/security/advisories/GHSA-4w5h-hx6r-28q7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/erweixin/RaTeX"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "ratex-parser has unbounded parser recursion that leads to stack overflow (process abort)"
}