CVE-2023-26303: 
Python vulnerability analysis and mitigation

A denial of service vulnerability was discovered in markdown-it-py versions prior to v2.2.0. The vulnerability, identified as CVE-2023-26303, allows attackers to cause system crashes by forcing null assertions through specially crafted input. The issue was discovered and disclosed in February 2023 (NVD, MITRE).

The vulnerability exists due to unnecessary assertions in the codebase that could be triggered with specially crafted input. The issue specifically affects the handling of null values in token children within the renderer.py, replacements.py, and smartquotes.py files. The vulnerability was fixed by replacing strict assertions with conditional checks (GitHub Commit).

When successfully exploited, this vulnerability can cause the markdown-it-py application to crash, resulting in a denial of service condition. This affects the availability of systems using the vulnerable versions of the library (NVD).

The recommended mitigation is to upgrade markdown-it-py to version 2.2.0 or later. The fix involves replacing strict assertions with proper conditional checks to handle null values gracefully (GitHub Commit).