CVE-2021-23368: 
JavaScript vulnerability analysis and mitigation

The vulnerability CVE-2021-23368 affects the PostCSS package versions from 7.0.0 and before 8.2.10. This Regular Expression Denial of Service (ReDoS) vulnerability was discovered during source map parsing and was disclosed on April 5, 2021 (NVD, Snyk).

The vulnerability exists in the source map parsing functionality where an unsafe regular expression pattern is used. The issue specifically occurs in the parsing of sourceMappingURL annotations. The vulnerable code used regex patterns that could lead to catastrophic backtracking, potentially causing the application to become unresponsive (GitHub Commit, GitHub Commit). The vulnerability has a CVSS score of 5.3 (medium severity) (Snyk).

When exploited, this vulnerability can cause performance degradation and interruptions in resource availability. While the attacker cannot completely deny service to legitimate users, the resources in the impacted component may become partially available or experience significant slowdowns due to excessive CPU consumption (Snyk).

The recommended mitigation is to upgrade PostCSS to version 7.0.36, 8.2.10 or higher. The vulnerability has been fixed by modifying the unsafe regular expression patterns used in source map parsing (Snyk).