CVE-2023-48051: 
Python vulnerability analysis and mitigation

An issue in /upydev/keygen.py in upydev v0.4.3 allows attackers to decrypt sensitive information via weak encryption padding. The vulnerability was discovered and disclosed in November 2023, affecting the cryptographic implementation in the upydev package. The issue is tracked as CVE-2023-48051 and has been assigned a CVSS v3.1 base score of 7.5 (HIGH) (NVD).

The vulnerability stems from the use of PKCS 1v1.5 padding in the RSA implementation within the keygen.py script. This padding scheme is known to be vulnerable to Bleichenbacher attacks, which is a chosen-ciphertext attack that can potentially allow attackers to decrypt sensitive information. The issue affects multiple locations in the codebase, including the RSA encryption and signature verification implementations (GitHub Issue).

The vulnerability allows attackers to potentially decrypt sensitive information protected by the affected cryptographic implementation. Due to the weak encryption padding, the confidentiality of encrypted data is compromised, which could lead to unauthorized access to sensitive information. The severity is reflected in the HIGH CVSS score, particularly impacting the confidentiality aspect of the security triad (NVD).

The recommended mitigation is to update the cryptographic implementation to use OAEP (Optimal Asymmetric Encryption Padding) for encryption and PSS (Probabilistic Signature Scheme) for signatures. These modern padding schemes offer better security against known attacks. For encryption, it is recommended to use padding.OAEP with SHA-256 for both the MGF1 function and the main algorithm (GitHub Issue).