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Cryptography CVE-2023-49083

HIGH
NULL Pointer Dereference (CWE-476)
2023-11-29 security-advisories@github.com
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A10:2025 - Mishandling of Exceptional Conditions
ASVS 5.0
V16 - Security Logging and Error Handling Null pointer safety, defensive checks
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could crash the application by dereferencing a null pointer by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 1.0% exploitation probability (EPSS)

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AnalysisAI

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Check pointers before dereferencing. Use static analysis tools to detect null pointer paths.

Affected Packages

pypi cryptography fix: 41.0.6

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as NULL Pointer Dereference (CWE-476), which allows attackers to crash the application by dereferencing a null pointer. cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Calling load_pem_pkcs7_certificates or load_der_pkcs7_certificates could lead to a NULL-pointer dereference and segfault. 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. This vulnerability has been patched in version 41.0.6. Affected products include: Cryptography.Io Cryptography. Version information: version 41.0.6..

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Calling load_pem_pkcs7_certificates or load_der_pkcs7_certificates could lead to a NULL-pointer dereference and segfault. 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. This vulnerability has been patched in version 41.0.6.

Threat Intelligence Overview

EPSS Score
1.0%
Top 42% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 1.0%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

59
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A null pointer dereference occurs when a program attempts to access memory through a pointer that has been set to NULL (address 0x0).

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:cryptography.io:cryptography:*:*:*:*:*:python:*:*
CVE-2026-69249 HIGH POC
8.7 Aug 03

Certificate path building in python-cryptography before 49.0.0 is exploitable as a denial-of-service vector by attackers

CVE-2026-69247 HIGH POC
8.2 Aug 03

PKCS#7 EnvelopedData decryption in the Python cryptography library (versions 44.0.0-49.x) leaks a Bleichenbacher oracle

CVE-2023-38325 HIGH POC
7.5 Jul 14

The cryptography package before 41.0.2 for Python mishandles SSH certificates that have critical options. Rated high sev

CVE-2026-69248 MEDIUM POC
6.9 Aug 03

Wildcard DNS SAN matching in python-cryptography's X.509 chain verifier prior to 49.0.0 allows a leaf certificate bearin

CVE-2023-23931 MEDIUM POC
6.5 Feb 07

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Rated medium sev

CVE-2026-26007 HIGH
8.2 Feb 10

Private-key information disclosure in the pyca/cryptography Python package (versions <= 46.0.4) arises because public-ke

CVE-2016-9243 HIGH
7.5 Mar 27

HKDF in cryptography before 1.5.2 returns an empty byte-string if used with a length less than algorithm.digest_size. Ra

CVE-2023-50782 HIGH
7.5 Feb 05

A flaw was found in the python-cryptography package. Rated high severity (CVSS 7.5), this vulnerability is remotely expl

CVE-2024-26130 HIGH
7.5 Feb 21

cryptography is a package designed to expose cryptographic primitives and recipes to Python developers. Rated high sever

CVE-2018-10903 HIGH
7.5 Jul 30

A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. Rated high severity (CVSS 7.5), this vulnerab

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