# CVE-2026-74233: Zbtlink MQWrt infosrvd Command Injection

> Remote unauthenticated attackers can execute arbitrary commands as root on Zbtlink routers via a command injection in the infosrvd service.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Aug 2026
- **Updated:** 27 Aug 2026
- **Also known as:** GHSA-2h7p-q23r-5gcf

## What is CVE-2026-74233?

CVE-2026-74233 is a critical command injection vulnerability in Unknown CTN720-W1, published on 27 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Zbtlink WE1326, WE357, WE5926, WE5926-WD, WE826-Q, WE826-T2, WE826-WD, WG108, and WG3526 firmware 19.1101, Zbtlink WE2426-C firmware 19.1112, Zbtlink WE5926-EC_QP firmware 20.0516, Zbtlink WF3526-P firmware 19.051, CTN720-W1, LF-1541, and MT7620N firmware 19.1101, and WRC1 firmware 20.0622 contain an unauthenticated command injection in the infosrvd service (UDP/9992). A remote unauthenticated attacker can send a crafted UDP packet to execute arbitrary commands as root. The service's authentication uses a hardcoded salt and an all-zero wildcard MAC bypass, rendering it ineffective.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command), CWE-321 (Use of Hard-coded Cryptographic Key)

## Which versions are affected by CVE-2026-74233?


## How do I fix CVE-2026-74233?

No fix has been published for CVE-2026-74233 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-74233 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-74233 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74233 and fix it if it is affected.

What it is: CVE-2026-74233 is a critical command injection vulnerability in Unknown CTN720-W1, published on 27 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-2026-74233 exists.

Affected product: Unknown CTN720-W1. 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-2026-74233/ (Markdown: https://insights.sbomify.com/CVE-2026-74233/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74233
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74233
- OSV: https://osv.dev/vulnerability/CVE-2026-74233

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74233/
Summaries are generated and may contain mistakes; the official description above is the record.