{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pymonocypher",
        "purl": "pkg:pypi/pymonocypher"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.0.2.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.1",
        "0.1.2",
        "0.1.3",
        "0.1.4",
        "3.1.0.0",
        "3.1.3.0",
        "3.1.3.1",
        "3.1.3.2",
        "3.1.3.3",
        "3.1.3.4",
        "3.1.3.5",
        "3.1.3.6",
        "4.0.2.1",
        "4.0.2.2",
        "4.0.2.3",
        "4.0.2.4",
        "4.0.2.5",
        "4.0.2.6",
        "4.0.2.7"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-53720",
    "GHSA-8f95-v3jq-cj86"
  ],
  "details": "### Impact\nThe argon2i_32 implementation does not check the nb_blocks size.  If the caller does not provide a sufficiently large buffer based on the API contract, then argon2i_32 will write past the end of the buffer and possibly corrupt the heap.\n\n### Patches\nFixed in 4.0.2.8, which now verifies that nb_blocks is large enough.  See [90ff5b1](https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86).\n\n### Workarounds\nProvide a correctly sized nb_blocks buffer.\n\npymonocypher thanks Haris (hextheshadow) for the vulnerability report, details, and recommended fix.",
  "id": "PYSEC-2026-3000",
  "modified": "2026-07-13T16:05:55.334297Z",
  "published": "2026-07-13T15:46:30.235469Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jetperch/pymonocypher/security/advisories/GHSA-8f95-v3jq-cj86"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jetperch/pymonocypher"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/pymonocypher"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-8f95-v3jq-cj86"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53720"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small"
}