# CVE-2026-6239: Authenticated Stack-based Buffer Overflow in ONVIF CreateUsers Service in TP-Link Tao C520WS

> An authenticated attacker can cause a denial of service in TP-Link Tapo C520WS cameras by triggering a stack-based buffer overflow in the ONVIF CreateUsers service.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Jun 2026
- **Updated:** 8 Jun 2026
- **Also known as:** GHSA-cpjh-84vm-rvxf

## What is CVE-2026-6239?

CVE-2026-6239 is a medium-severity memory corruption vulnerability in TP-Link Systems Inc. Tapo C520WS v2, published on 5 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A stack‑based
buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where
the device fails to properly validate the number of XML user nodes during
request processing. An authenticated attacker can send a specially crafted
ONVIF request containing an excessive number of user entries to trigger memory
corruption.

Successful
exploitation may cause the ONVIF management service to terminate unexpectedly,
resulting in a denial‑of‑service (DoS) condition that disrupts device
configuration and management functions.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-6239?


## How do I fix CVE-2026-6239?

No fix has been published for CVE-2026-6239 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6239 being exploited?

There is no known exploitation of CVE-2026-6239 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6239 and fix it if it is affected.

What it is: CVE-2026-6239 is a medium-severity memory corruption vulnerability in TP-Link Systems Inc. Tapo C520WS v2, published on 5 Jun 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-2026-6239 in the wild and no public exploit code.

Affected product: TP-Link Systems Inc. Tapo C520WS v2. 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-2026-6239/ (Markdown: https://insights.sbomify.com/CVE-2026-6239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6239
- OSV: https://osv.dev/vulnerability/CVE-2026-6239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6239/
Summaries are generated and may contain mistakes; the official description above is the record.