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Medium

Null pointer dereference in PKCS12 parsing

  • Disclosed: 26.01.2024
  • Updated: 11.10.2026 15:17

Issue summary: Processing a maliciously formatted PKCS12 file may lead OpenSSL to crash leading to a potential Denial of Service attack

Impact summary: Applications loading files in the PKCS12 format from untrusted sources might terminate abruptly.

A file in PKCS12 format can contain certificates and keys and may come from an untrusted source. The PKCS12 specification allows certain fields to be NULL, but OpenSSL does not correctly check for this case. This can lead to a NULL pointer dereference that results in OpenSSL crashing. If an application processes PKCS12 files from an untrusted source using the OpenSSL APIs then that application will be vulnerable to this issue.

OpenSSL APIs that are vulnerable to this are: PKCS12_parse(), PKCS12_unpack_p7data(), PKCS12_unpack_p7encdata(), PKCS12_unpack_authsafes() and PKCS12_newpass().

We have also fixed a similar issue in SMIME_write_PKCS7(). However since this function is related to writing data we do not consider it security significant.

The FIPS modules in 3.2, 3.1 and 3.0 are not affected by this issue.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) cryptography < 42.0.2 42.0.2

References

CVSS score 5.5/10
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-476
Platform
Python (PyPI)
Package
cryptography
Disclosed
26.01.2024
Updated
11.10.2026 15:17

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-1285 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-9v9h-cgj8-h64p - CC BY 4.0

Vulnerability history: cryptography

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (24) in the archive
Total entries
24
First → latest
03.2017 08.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 12
  • Medium 7
  • Low 5

Disclosures per year

Severity:
  1. python-cryptography: Duplicate self-signed intermediates can cause exponential path-building
    High CVE-2026-69249 >= 42.0.0, < 49.0.0 49.0.0
  2. cryptography: PKCS#7 EnvelopedData decryption exposes a Bleichenbacher oracle through distinguishable errors and timing
    High CVE-2026-69247 >= 44.0.0, < 50.0.0 50.0.0
  3. Vulnerable OpenSSL included in cryptography wheels
    High · 7.5 ghsa-537c-gmf6-5ccf >= 0.5.0, < 48.0.1 48.0.1
  4. cryptography Vulnerable to a Subgroup Attack Due to Missing Subgroup Validation for SECT Curves
    High CVE-2026-26007 < 46.0.5 46.0.5
  5. cryptography NULL pointer dereference with pkcs12.serialize_key_and_certificates when called with a non-matching certificate and private key and an hmac_hash override
    High · 7.5 CVE-2024-26130 >= 38.0.0, < 42.0.4 42.0.4
  6. Python Cryptography package vulnerable to Bleichenbacher timing oracle attack
    High · 7.5 CVE-2023-50782 < 42.0.0 42.0.0
  7. Null pointer dereference in PKCS12 parsing this entry
    Medium · 5.5 CVE-2024-0727 < 42.0.2 42.0.2
  8. cryptography mishandles SSH certificates
    High · 7.5 CVE-2023-38325 >= 40.0.0, < 41.0.2 41.0.2
  9. Vulnerable OpenSSL included in cryptography wheels
    High · 7.4 CVE-2023-0286 >= 0.8.1, < 39.0.1 39.0.1
  10. PyCA Cryptography symmetrically encrypting large values can lead to integer overflow
    High · 9.1 CVE-2020-36242 >= 3.1, < 3.3.2 3.3.2
  11. RSA decryption vulnerable to Bleichenbacher timing vulnerability
    High · 5.9 CVE-2020-25659 < 3.2 3.2
  12. PyCA Cryptography vulnerable to GCM tag forgery
    High · 7.5 CVE-2018-10903 >= 1.9.0, < 2.3 2.3
  13. Improper input validation in cryptography
    High · 7.5 CVE-2016-9243 < 1.5.3 1.5.3

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