CVE-2026-88831

Busybox: busybox: httpd silently fails open when ip deny rules contain invalid cidr prefix lengths

Published Sep 23, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

Audit all BusyBox httpd configuration files for syntactically valid CIDR prefix lengths. Implement network-level access controls (iptables/nftables) as the primary enforcement layer rather than relying on application-level ACLs.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Busybox
Busybox busybox
Redhat hardened Images
Vendors & Products Busybox
Busybox busybox
Redhat hardened Images
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Busybox: busybox: httpd silently fails open when ip deny rules contain invalid cidr prefix lengths
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-636
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Sep 25, 2026, 10:28 PM
Reserved
Sep 10, 2026, 9:42 AM
Status
Awaiting Analysis
Published
Sep 23, 2026, 6:17 PM
Modified
Sep 25, 2026, 11:16 PM
Severity
Moderate
Public date
Sep 23, 2026, 4:35 PM