CVE-2026-88831

BusyBox httpd IP deny rules with invalid CIDR prefix lengths fail open, leaving a parsed IP with a zeroed mask so the rule matches no clients.

  • Published Sep 23, 2026
  • CVSS 5.3 medium
  • 0.2% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-88831 at the National Vulnerability Database