Medium severity · published Sep 23, 2026
CVE-2026-88831
Busybox: busybox: httpd silently fails open when ip deny rules contain invalid cidr prefix lengths
5.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Hardened Images · Red Hat
All versions, or not specified · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-88831
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-88831
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:72111
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-88831
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2531346
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