CVE-2021-4305

CVE-2021-4305 is a problematic vulnerability affecting the Woorank/bridgeline robots-txt-guard library, specifically within the makePathPattern function in lib/patterns.js. This flaw stems from inefficient regular expression complexity when processing the 'pattern' argument. Rated as High severity (CVSS 7.5), it allows an unauthenticated attacker to cause a denial of service (availability impact) with low attack complexity over the network. While the exploit has been publicly disclosed, there is no evidence of active exploitation, nor are there readily available exploit modules in common frameworks like Metasploit or Nuclei, and it has garnered minimal community discussion or media coverage.