# CVE-2026-9443: Edimax BR-6478AC POST Request formL2TPSetup buffer overflow

> Remote attackers can trigger a buffer overflow in the L2TP setup handler of Edimax BR-6478AC routers, potentially leading to code execution or service disruption.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 May 2026
- **Updated:** 26 May 2026
- **Also known as:** GHSA-349r-6q9h-2pfh

## What is CVE-2026-9443?

CVE-2026-9443 is a high-severity memory corruption vulnerability in Edimax BR-6478AC, published on 25 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security vulnerability has been detected in Edimax BR-6478AC 1.23. This vulnerability affects the function formL2TPSetup of the file /goform/formL2TPSetup of the component POST Request Handler. The manipulation of the argument L2TPUserName leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-9443?


## How do I fix CVE-2026-9443?

No fix has been published for CVE-2026-9443 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9443 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9443 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9443 and fix it if it is affected.

What it is: CVE-2026-9443 is a high-severity memory corruption vulnerability in Edimax BR-6478AC, published on 25 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9443 exists.

Affected product: Edimax BR-6478AC. 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-2026-9443/ (Markdown: https://insights.sbomify.com/CVE-2026-9443/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9443
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9443
- OSV: https://osv.dev/vulnerability/CVE-2026-9443

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9443/
Summaries are generated and may contain mistakes; the official description above is the record.