# CVE-2026-124739: Busybox: httpd stack buffer overflow via an "i:" rule in a subdirectory httpd.conf

> An attacker able to write a subdirectory httpd.conf can overflow a stack buffer in BusyBox httpd to run code or crash it.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** No
- **Fix available:** No
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** GHSA-cfm6-7rfg-w924, UBUNTU-CVE-2026-124739

## What is CVE-2026-124739?

CVE-2026-124739 is a high-severity memory corruption vulnerability in Red Hat Enterprise Linux 6, published on 11 Nov 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-124739?

An affected version is exposed as installed. No special setting or call is needed.


## How do I fix CVE-2026-124739?

No fix has been published for CVE-2026-124739 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-124739 being exploited?

There is no known exploitation of CVE-2026-124739 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-124739 and fix it if it is affected.

What it is: CVE-2026-124739 is a high-severity memory corruption vulnerability in Red Hat Enterprise Linux 6, published on 11 Nov 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-124739 in the wild and no public exploit code.
Exposure: An affected version is exposed as installed. No special setting or call is needed.

Affected product: Red Hat Enterprise Linux 6. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-124739/ (Markdown: https://insights.sbomify.com/CVE-2026-124739/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-124739
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124739
- OSV: https://osv.dev/vulnerability/CVE-2026-124739

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-124739/
Summaries are generated and may contain mistakes; the official description above is the record.