# CVE-2026-77683: Comfast CF-N1-S mbox-config system command injection

> Remote attackers can execute arbitrary system commands on Comfast CF-N1-S routers via the mbox-config interface, requiring immediate attention from network administrators.

- **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:** 21 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-hh37-xhg2-x62w

## What is CVE-2026-77683?

CVE-2026-77683 is a critical command injection vulnerability in Comfast CF-N1-S, published on 21 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A security flaw has been discovered in Comfast CF-N1-S 2.6.0.1. Affected by this issue is the function system of the file /cgi-bin/mbox-config?method=SET&section=ntp_timezone. The manipulation of the argument timestr results in command injection. The attack can be launched remotely. The exploit has been released to the public and may be used for attacks.

Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command), CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-77683?


## How do I fix CVE-2026-77683?

No fix has been published for CVE-2026-77683 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77683 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77683 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77683 and fix it if it is affected.

What it is: CVE-2026-77683 is a critical command injection vulnerability in Comfast CF-N1-S, published on 21 Aug 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-2026-77683 exists.

Affected product: Comfast CF-N1-S. 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-2026-77683/ (Markdown: https://insights.sbomify.com/CVE-2026-77683/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77683
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77683
- OSV: https://osv.dev/vulnerability/CVE-2026-77683

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77683/
Summaries are generated and may contain mistakes; the official description above is the record.