# CVE-2026-85031: TOTOLINK CP450 cstecgi.cgi buffer overflow

> Remote attackers can trigger a buffer overflow in the CP450 web interface via the topicurl parameter, potentially leading to code execution.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-xjrp-q25x-8wpw

## What is CVE-2026-85031?

CVE-2026-85031 is a critical memory corruption vulnerability in TOTOLINK CP450, published on 3 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was found in TOTOLINK CP450 4.1.0. The impacted element is an unknown function of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument topicurl results in buffer overflow. Remote exploitation of the attack is possible.

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-2026-85031?


## How do I fix CVE-2026-85031?

No fix has been published for CVE-2026-85031 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85031 being exploited?

There is no known exploitation of CVE-2026-85031 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85031 and fix it if it is affected.

What it is: CVE-2026-85031 is a critical memory corruption vulnerability in TOTOLINK CP450, published on 3 Sep 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-2026-85031 in the wild and no public exploit code.

Affected product: TOTOLINK CP450. 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-2026-85031/ (Markdown: https://insights.sbomify.com/CVE-2026-85031/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85031
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85031
- OSV: https://osv.dev/vulnerability/CVE-2026-85031

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85031/
Summaries are generated and may contain mistakes; the official description above is the record.