CVE-2026-88831
Busybox: busybox: httpd silently fails open when ip deny rules contain invalid cidr prefix lengths
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.
INFO
Published Date :
Sept. 23, 2026, 6:17 p.m.
Last Modified :
Sept. 23, 2026, 6:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | 53f830b8-0a3f-465b-8143-3b8a9948e749 | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update BusyBox httpd to the latest version.
- Ensure IP deny rules use valid CIDR prefix lengths.
- Validate firewall rules after update.
- Test IP access controls.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-88831.
| URL | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-88831 | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2531346 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-88831 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-88831
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-88831 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-88831 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 23, 2026
Action Type Old Value New Value 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-636 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/88xxx/CVE-2026-88831.json">CVE-2026-88831</a> Added Reference https://access.redhat.com/security/cve/CVE-2026-88831 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2531346