{"id":"CVE-2026-88831","title":"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.","summary":"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.","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-636"],"vendor":"Red Hat","product":"busybox-main","affected":["busybox-main (all versions)"],"published":"2026-09-23","updated":"2026-09-25","sourceUpdated":"2026-09-25T23:16:54.457","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88831","references":[{"url":"https://access.redhat.com/errata/RHSA-2026:72111","label":"secalert@redhat.com"},{"url":"https://access.redhat.com/security/cve/CVE-2026-88831","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2531346","label":"secalert@redhat.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88831.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-88831"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-88831"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-23T18:08:33.797869Z"},"epss":0.00205,"epssPercentile":0.09325,"ingestedAt":"2026-09-23T18:29:33.145Z","patched":["hardened_images"],"slug":"CVE-2026-88831","body":"## Overview\n\nBusyBox 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · affected: Red Hat Hardened Images · no fix planned: Red Hat Hardened Images · updated 2026-09-24 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88831.json)\n- **RHSA-2026:72111** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:72111)","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}