CVE-2026-63567

{
  "etk_id": "ETK-2026-323",
  "cve_id": "CVE-2026-63567",
  "display_id": "CVE-2026-63567",
  "ghsa_id": "GHSA-6w4x-4wpp-m6r4",
  "euvd_id": "EUVD-2026-91218",
  "status": "published",
  "anchor_state": "anchored",
  "title": "CBC padding oracle in BouncyCastle.Cryptography IesEngine",
  "summary": "BouncyCastle.Cryptography versions before 2.7.0 are affected when applications directly use IesEngine with a padded block cipher. An attacker who has intercepted ciphertext and can submit altered ciphertext for decryption with the same key pair may recover plaintext from response differences; stream-mode IES is not affected.",
  "mitigation": "Upgrade BouncyCastle.Cryptography to version 2.7.0. Until upgraded, avoid directly configuring IesEngine with padded block-cipher modes.",
  "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": [
    203
  ],
  "cvss_score": 8.2,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
  "epss_score": 0.0047,
  "epss_percentile": 0.3916,
  "epss_asof": "2026-10-20",
  "automation": "contextual",
  "check": true,
  "check_confidence_basis": "mechanism_verified",
  "exploit": false,
  "pipeline_minutes": 12.648143766666667,
  "t0_at": "2026-10-02T06:58:32.487000+00:00",
  "signals": {
    "check": {
      "at": "2026-10-02T09:22:12.189979+00:00",
      "days": 0.09976508077546296,
      "is_lower_bound": false,
      "measured_at": "2026-10-02T06:58:32.487000+00:00",
      "url": null
    },
    "trigger_signal": {
      "at": "2026-10-02T06:58:32.487000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-10-02T06:58:32.487000+00:00",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63567"
    }
  }
}