CVE-2023-49083 in cryptography
Summary
by MITRE • 11/29/2023
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.
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Analysis
by VulDB Data Team • 09/12/2025
The vulnerability identified as CVE-2023-49083 resides within the cryptography Python package, a widely-used library that provides cryptographic primitives and recipes for Python developers. This package serves as a foundational component for secure communication and data protection in numerous applications across the Python ecosystem. The flaw manifests specifically when applications attempt to deserialize PKCS7 certificate blobs using the `load_pem_pkcs7_certificates` or `load_der_pkcs7_certificates` functions. These functions are commonly employed in scenarios involving certificate validation, secure communication protocols, and digital signature verification processes.
The technical nature of this vulnerability constitutes a NULL-pointer dereference condition that leads to a segmentation fault or segfault. This occurs when the cryptographic library attempts to process malformed or improperly structured PKCS7 certificate data without adequate validation of pointer references. The underlying mechanism involves the library's failure to properly handle edge cases in certificate parsing, particularly when encountering unexpected data formats or incomplete certificate structures. When the parsing routine encounters a NULL reference that it attempts to dereference, the operating system terminates the process with a segmentation fault, effectively crashing the application. This behavior represents a classic software defect pattern that aligns with CWE-476, which specifically addresses NULL pointer dereference vulnerabilities in software systems.
The operational impact of this vulnerability extends beyond simple application crashes to potentially compromise system availability and stability. Any application that relies on the cryptography package for PKCS7 certificate processing becomes susceptible to denial of service attacks through carefully crafted malicious certificate data. This vulnerability is particularly concerning in production environments where continuous availability is critical, as adversaries could exploit this weakness to disrupt services by sending malformed certificate data to applications that process PKCS7 certificates. The cascading effects could be significant in distributed systems where certificate validation is a frequent operation, potentially leading to widespread service disruption. Furthermore, the vulnerability could be leveraged in broader attack chains where the initial DoS condition might be used as a stepping stone for more sophisticated exploitation techniques.
Mitigation strategies for CVE-2023-49083 focus primarily on updating to the patched version 41.0.6 of the cryptography package. Organizations should conduct immediate vulnerability assessments to identify applications that utilize the affected functions and prioritize patching efforts accordingly. Security teams should implement monitoring solutions to detect potential exploitation attempts through unusual certificate processing patterns or application crash events. Additionally, defensive coding practices should be enforced to include proper input validation and error handling around certificate processing functions. The ATT&CK framework categorizes this vulnerability under the T1499.004 technique for "Cloud Compute Infrastructure Compromise" when considering the broader impact on system availability, and under T1566.001 for "Phishing" when considering potential social engineering aspects of delivering malicious certificate data. Organizations should also consider implementing network segmentation and access controls to limit exposure of applications that process external certificate data, reducing the attack surface for this particular vulnerability.