{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-71892",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-71892",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-10-03T08:30:26.982Z",
    "updatedAt": "2026-10-05T16:58:40.411Z",
    "importedAt": "2026-10-24T01:58:25.636Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "CMS key-transport recipient key-size validation never runs for RFC 9709 HKDF-derived keys",
      "summary": "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's 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's 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).",
      "affected": [
        {
          "vendor": "Legion of the Bouncy Castle Inc.",
          "product": "BC-JAVA",
          "packageName": "bcpkix",
          "collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java/",
          "platforms": [
            "all"
          ],
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "1.78",
              "status": "affected",
              "versionType": "maven",
              "lessThan": "1.86"
            }
          ]
        },
        {
          "vendor": "Legion of the Bouncy Castle Inc.",
          "product": "BC-FJA",
          "packageName": "bcpkix-fips",
          "collectionURL": "https://www.bouncycastle.org/download/bouncy-castle-java-fips/",
          "platforms": [
            "all"
          ],
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "2.0.7",
              "status": "affected",
              "versionType": "maven",
              "lessThan": "2.0.13"
            },
            {
              "version": "2.1.0",
              "status": "affected",
              "versionType": "maven",
              "lessThan": "2.1.13"
            }
          ]
        }
      ]
    }
  }
}