# CVE-2026-124741: Busybox: stack buffer overflow in udhcpc6 send_d6_renew() and send_d6_release()

> A malicious local DHCPv6 server can overflow a stack buffer in BusyBox udhcpc6, executing code as root or crashing it.

- **Severity:** High 7.6 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** No
- **Fix available:** No
- **Published:** 11 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-6p28-q7pv-rxcx, UBUNTU-CVE-2026-124741

## What is CVE-2026-124741?

CVE-2026-124741 is a high-severity memory corruption vulnerability in Red Hat Enterprise Linux 6, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in BusyBox. The udhcpc6 DHCPv6 client does not properly validate the size of network options sent by a server before copying them into memory. A malicious DHCPv6 server on the local network can exploit this flaw by sending a crafted reply, triggering a stack-based buffer overflow. This vulnerability could allow an attacker to achieve arbitrary code execution with root privileges or cause a denial of service (DoS) crash.

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

## Which versions are affected by CVE-2026-124741?

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


## How do I fix CVE-2026-124741?

No fix has been published for CVE-2026-124741 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-124741 being exploited?

There is no known exploitation of CVE-2026-124741 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-124741 and fix it if it is affected.

What it is: CVE-2026-124741 is a high-severity memory corruption vulnerability in Red Hat Enterprise Linux 6, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-124741 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-2026-124741/ (Markdown: https://insights.sbomify.com/CVE-2026-124741/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-124741
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124741
- OSV: https://osv.dev/vulnerability/CVE-2026-124741

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-124741/
Summaries are generated and may contain mistakes; the official description above is the record.