{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.6.4"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "628e36ecbb5277a3f01572ce418ef54271b165a5"
            },
            {
              "fixed": "72e4803405816c371ed3b2cb4be181c47f038406"
            }
          ],
          "repo": "https://github.com/pyasn1/pyasn1",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-m4p7-r5rc-7g4j"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59884.json"
  },
  "details": "pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.",
  "id": "CVE-2026-59884",
  "modified": "2026-07-17T03:42:02.056647803Z",
  "published": "2026-07-14T16:41:10.277Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59884.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/pyasn1/pyasn1/security/advisories/GHSA-m4p7-r5rc-7g4j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59884"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pyasn1/pyasn1/commit/628e36ecbb5277a3f01572ce418ef54271b165a5"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs"
}