CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HCVE-2026-124739 Busybox: httpd stack buffer overflow via an "i:" rule in a subdirectory httpd.conf
High (7.5) in red hat. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
- EPSS
- 0.5% estimated probability of exploitation activity in the next 30 days; 41st percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: total, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-787 Out-of-bounds Write
- Published
- Modified
- Assigned by
- redhat (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
- red hat:red hat enterprise linux 6
- red hat:red hat hardened images
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 20.04:LTS, 22.04:LTS, 24.04:LTS and 5 more | busybox | no fix listed | UBUNTU-CVE-2026-124739 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.
Red Hat
Red Hat rates this Important.
This vulnerability is rated as Important because successful exploitation allows a local user with write access to web-accessible directories to execute arbitrary code with elevated root privileges or trigger a denial of service. Within Red Hat environments, BusyBox is not deployed as a standard web server by default, significantly limiting exposure in standard installations. Exploitation specifically requires the BusyBox httpd service to be actively running and serving content from directories where untrusted users possess write permissions to introduce or modify local configuration files.
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.
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | busybox | Affected | |
| Red Hat Hardened Images | busybox | Affected |
Contains Red Hat Security Data © Red Hat, Inc., licensed under CC BY 4.0. Source: https://access.redhat.com/security/data. Modified: reformatted. Red Hat's page for CVE-2026-124739.