CVE-2026-63568

{
  "etk_id": "ETK-2026-319",
  "cve_id": "CVE-2026-63568",
  "display_id": "CVE-2026-63568",
  "ghsa_id": "GHSA-mm8p-p4g9-932c",
  "euvd_id": "EUVD-2026-91219",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Unbounded MAC iteration denial of service in BouncyCastle.Cryptography",
  "summary": "BouncyCastle.Cryptography before 2.7.0 can consume excessive CPU while validating password-based MACs in CMP messages or CRMF certificate requests. An unauthenticated remote attacker can cause denial of service if the application processes attacker-supplied requests and uses PKMacBuilder without an explicit iteration limit.",
  "mitigation": "Upgrade BouncyCastle.Cryptography to version 2.7.0 or later. Until upgraded, construct PKMacBuilder with an explicit maximum iteration count and restrict processing of untrusted CMP and CRMF requests where possible.",
  "vendor": "Legion of the Bouncy Castle Inc.",
  "product": "bc-csharp",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 0, < 2.7.0"
      ],
      "ecosystem": null,
      "fixed_versions": [
        "2.7.0"
      ],
      "package_name": "BouncyCastle.Cryptography",
      "purl": null
    }
  ],
  "cwes": [
    770
  ],
  "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": 0.0032,
  "epss_percentile": 0.2342,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": true,
  "check_confidence_basis": "mechanism_verified",
  "exploit": false,
  "pipeline_minutes": 14.586429716666666,
  "t0_at": "2026-10-02T06:59:30.557000+00:00",
  "signals": {
    "check": {
      "at": "2026-10-02T08:52:20.561666+00:00",
      "days": 0.07835653548611111,
      "is_lower_bound": false,
      "measured_at": "2026-10-02T06:59:30.557000+00:00",
      "url": null
    },
    "trigger_signal": {
      "at": "2026-10-02T06:59:30.557000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-02T06:59:30.557000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63568"
    }
  }
}