{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "3.28.0"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5370fb26fbf034ecd11d3026b6ad639b5fff493f"
            },
            {
              "fixed": "1f7a716d39b5605bb8a83b0c3c97a6ce386609ef"
            }
          ],
          "repo": "https://github.com/freerdp/freerdp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-pjqx-v446-x7fc"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-122"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64620.json"
  },
  "details": "FreeRDP before 3.28.0 (affected \u003c=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length \u003e out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.",
  "id": "CVE-2026-64620",
  "modified": "2026-07-22T05:29:47.756035396Z",
  "published": "2026-07-20T12:04:53.105Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64620.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pjqx-v446-x7fc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64620"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/freerdp-before-heap-buffer-overflow-via-crypto-rsa-common"
    },
    {
      "type": "FIX",
      "url": "https://github.com/FreeRDP/FreeRDP/commit/1f7a716d39b5605bb8a83b0c3c97a6ce386609ef"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "FreeRDP before 3.28.0 Heap Buffer Overflow via crypto_rsa_common"
}