CVE-2023-49083 is a medium-severity (CVSS 5.9) NULL Pointer Dereference vulnerability in cryptography. 1 public exploit reference exists, so weaponization risk is real. A fix is available for cryptography — see the affected versions and patch details below.
cryptography vulnerable to NULL-dereference when loading PKCS7 certificates
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-49083.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-49083 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
cryptographyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cryptography | ≥ 3.1&&< 41.0.6 | 41.0.6pip install --upgrade 'cryptography==41.0.6' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cryptography, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update cryptography to 41.0.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-49083 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-49083 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-49083. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability arises when functions like "load_pem_pkcs7_certificates" or "load_der_pkcs7_certificates" are invoked, triggering the issue during the deserialization of PKCS7 blobs or certificates. The moderate rating is based on the fact that the vulnerability can lead to a segmentation fault, posing a risk of…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.4 for RHEL 8 | automation-controller-0:4.5.5-2.el8ap | RHSA-2024:1640 |
| Red Hat Ansible Automation Platform 2.4 for RHEL 8 | python3x-cryptography-0:42.0.5-1.el8ap | RHSA-2024:3781 |
| Red Hat Enterprise Linux 8 | python3.11-cryptography-0:37.0.2-6.el8 | RHSA-2024:3105 |
| Red Hat Enterprise Linux 8 | python-cryptography-0:3.2.1-8.el8_10 | RHSA-2025:14553 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | python-cryptography-0:3.2.1-4.el8_4.1 | RHSA-2025:13098 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | python-cryptography-0:3.2.1-5.1.el8_6.1 | RHSA-2025:13104 |
| Red Hat Enterprise Linux 8.8 Extended Update Support | python3.11-cryptography-0:37.0.2-5.el8_8.1 | RHSA-2024:10965 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | python-cryptography-0:3.2.1-6.el8_8 | RHSA-2025:13100 |
Frequently Asked Questions
Is CVE-2023-49083 in your dependencies?
O3 Security finds CVE-2023-49083 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.