# CVE-2026-79911: TOTOLINK N600R CGI cstecgi.cgi setSystemConfig stack-based overflow

> A remote attacker can trigger a stack-based buffer overflow in the TOTOLINK N600R router's CGI handler via the Hostname argument, potentially executing arbitrary code.

- **Severity:** Critical 10.0 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Aug 2026
- **Updated:** 27 Aug 2026
- **Also known as:** GHSA-wgfc-85p2-7526

## What is CVE-2026-79911?

CVE-2026-79911 is a critical memory corruption vulnerability in TOTOLINK N600R, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security vulnerability has been detected in TOTOLINK N600R 4.3.0cu.7647_B20210106. The affected element is the function setSystemConfig of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument Hostname leads to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-79911?


## How do I fix CVE-2026-79911?

No fix has been published for CVE-2026-79911 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-79911 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79911 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-79911 and fix it if it is affected.

What it is: CVE-2026-79911 is a critical memory corruption vulnerability in TOTOLINK N600R, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79911 exists.

Affected product: TOTOLINK N600R. 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-2026-79911/ (Markdown: https://insights.sbomify.com/CVE-2026-79911/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-79911
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-79911
- OSV: https://osv.dev/vulnerability/CVE-2026-79911

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-79911/
Summaries are generated and may contain mistakes; the official description above is the record.