CVE-2021-29495: 
Nim vulnerability analysis and mitigation

Nim, a statically typed compiled systems programming language, contained a security vulnerability (CVE-2021-29495) in its standard library before version 1.4.2. The vulnerability involved the httpClient SSL/TLS certificate verification being disabled by default, potentially exposing applications to man-in-the-middle attacks (GitHub Advisory, NVD).

The vulnerability was assigned a CVSS v3.1 base score of 7.5 (HIGH) by NVD and 5.9 (MEDIUM) by GitHub. The vulnerability is classified under CWE-295 (Improper Certificate Validation). The issue specifically relates to the default configuration of the httpClient component in the Nim standard library, where SSL/TLS certificate verification was disabled by default, potentially allowing for unauthorized access and data manipulation (NVD).

The vulnerability could allow attackers to perform man-in-the-middle attacks due to the lack of proper certificate validation. This could potentially lead to unauthorized data manipulation and compromise of secure communications (GitHub Advisory).

Users can mitigate this vulnerability by either upgrading to Nim version 1.4.2 or later, which includes the patch, or by explicitly setting 'verifyMode = CVerifyPeer' as documented in the configuration (GitHub Advisory).