CVE-2026-79770: Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokeniz

Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokenizer affecting string-literal and identifier tokenization. Attackers can inject adversarial CSS selectors into methods like Node#css, Node#at_css, and Searchable#search to cause exponential regex backtracking and denial of service.