CVE-2026-124683

{
  "etk_id": "ETK-2026-3971",
  "cve_id": "CVE-2026-124683",
  "display_id": "CVE-2026-124683",
  "ghsa_id": "GHSA-297v-g8mm-qj4h",
  "euvd_id": "EUVD-2026-120086",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Quadratic tokenization in Langium indentation-aware lexer",
  "summary": "Eclipse Langium 3.2.0 through 4.4.0 can consume excessive CPU while tokenizing specially structured, indentation-heavy documents when the opt-in indentation-aware lexer and token builder are enabled. An attacker able to submit such a document can stall the Node.js event loop and disrupt other users handled by that process; deployments using the default lexer and token builder are not affected.",
  "mitigation": "Use DefaultLexer and DefaultTokenBuilder instead of the indentation-aware components where possible. Until a fixed Langium release is available, limit or reject untrusted large and indentation-heavy documents before synchronous tokenization.",
  "vendor": "Eclipse Foundation",
  "product": "Eclipse Langium",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 3.2.0, <= 4.4.0"
      ],
      "ecosystem": null,
      "fixed_versions": [],
      "package_name": "Eclipse Langium",
      "purl": null
    }
  ],
  "cwes": [
    407
  ],
  "cvss_score": 8.7,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "contextual",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 10.35659385,
  "t0_at": "2026-11-09T16:02:50.370000+00:00",
  "signals": {
    "trigger_signal": {
      "at": "2026-11-09T16:02:50.370000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-11-09T16:02:50.370000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-124683"
    }
  }
}