{
  "cveId": "CVE-2026-71892",
  "url": "https://patchblox.com/security/cve/CVE-2026-71892",
  "summary": "CVE-2026-71892 is fixed in bouncycastle on 1 platform, first by DEBIAN-CVE-2026-71892, released October 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "bouncycastle: In Bouncy Castle for Java before 1.86, the opt-in key-size validation on CMS key-transport recipients, org.bouncycast...",
  "description": "In Bouncy Castle for Java before 1.86, the opt-in key-size validation on CMS key-transport recipients, org.bouncycastle.cms.jcajce.JceKeyTransRecipient.setKeySizeValidation(true), never ran for a message using RFC 9709 content-encryption key derivation (id-alg-cek-hkdf-sha256). The branch that should have selected the actual content-encryption algorithm carried in the key derivation AlgorithmIdentifier\u0027s parameters compared the encrypted-key byte array against the id-alg-cek-hkdf-sha256 object identifier, a comparison between a byte array and an ASN1ObjectIdentifier that is false for every possible input, so the check fell through to a key-size lookup on the outer wrapper OID. That OID identifies a key-derivation construction rather than a cipher and has no registered key size, so the size comparison was skipped entirely. A key-transport EnvelopedData or AuthEnvelopedData whose transported, HKDF-derived content-encryption key did not match the key size of the advertised content-encryption algorithm was therefore accepted even with validation explicitly enabled, silently defeating the only mechanism the API offers for enforcing recovered key size. The recipient now dispatches on the content-encryption AlgorithmIdentifier\u0027s algorithm OID, so validation checks the recovered key against the inner content-encryption algorithm. Messages with a matching key size, non-HKDF messages, and recipients that do not enable validation are unaffected. This issue also affects Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).",
  "published": "2026-10-03T09:17:05Z",
  "severity": "",
  "epss": 0.00173,
  "epssPercentile": 0.06784,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "bouncycastle",
      "release": "Debian 14",
      "fixedVersion": "1.86-1",
      "fix": "DEBIAN-CVE-2026-71892",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-71892",
      "released": "2026-10-03T21:16:35Z"
    },
    {
      "platform": "linux",
      "product": "bouncycastle",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "1.86-160000.1.1",
      "fix": "OPENSUSE-SU-2026:22169-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-22169-1",
      "released": "2026-11-07T00:47:19Z"
    },
    {
      "platform": "linux",
      "product": "bouncycastle",
      "release": "sles 15.6",
      "fixedVersion": "1.86-150200.3.41.1",
      "fix": "SUSE-SU-2026:4797-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4797-1",
      "released": "2026-11-07T00:42:08Z"
    },
    {
      "platform": "linux",
      "product": "bouncycastle",
      "release": "sles 15.7",
      "fixedVersion": "1.86-150200.3.41.1",
      "fix": "SUSE-SU-2026:4797-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-4797-1",
      "released": "2026-11-07T00:42:08Z"
    },
    {
      "platform": "linux",
      "product": "bouncycastle",
      "release": "sles 16.0",
      "fixedVersion": "1.86-160000.1.1",
      "fix": "SUSE-SU-2026:24461-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-24461-1",
      "released": "2026-11-07T00:44:01Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}