Busybox: httpd stack buffer overflow via an "i:" rule in a subdirectory httpd.conf
Summary
| CVE | CVE-2026-124739 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-11 11:17:16 UTC |
| Updated | 2026-11-11 11:17:17 UTC |
| Description | A flaw was found in BusyBox. When the httpd web server processes subdirectory configuration files, an overly long index page name can trigger a stack-based buffer overflow. An attacker with permissions to write to a subdirectory configuration file could exploit this vulnerability to execute arbitrary code with elevated privileges or cause a denial of service (DoS) by crashing the server process. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Problem Types: CWE-787 | CWE-787 Out-of-bounds Write
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Hardened Images | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-124739 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank ducanhluu for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-10-25T13:36:34.000Z | Reported to Red Hat. |
| CNA | 2026-11-11T09:15:15.000Z | Made public. |
Workarounds
CNA: Prevent untrusted users from creating or modifying configuration files by restricting write permissions on all web root and subdirectory paths served by BusyBox httpd to administrative accounts only: chmod -R o-w /path/to/webroot Additionally, ensure the BusyBox httpd process drops elevated privileges by specifying an unprivileged user with the `-u` flag upon execution: busybox httpd -u nobody Restarting the daemon is required for process-level flag changes to take effect, which will temporarily terminate active network connections. Caveats: Running under a non-privileged user account prevents binding directly to privileged ports (below 1024) without additional system capabilities or port forwarding, and restricting directory permissions may interfere with workflows that require unprivileged file uploads.