# CVE-2026-2548: WAYOS FBM-220G rc sub_40F820 command injection

> Remote attackers can execute arbitrary commands on WAYOS FBM-220G devices via manipulated UPnP arguments in the rc script.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/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:** 16 Feb 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-vfjw-j4jg-frr6

## What is CVE-2026-2548?

CVE-2026-2548 is a medium-severity command injection vulnerability in WAYOS FBM-220G, published on 16 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw has been found in WAYOS FBM-220G 24.10.19. This affects the function sub_40F820 of the file rc. Executing a manipulation of the argument upnp_waniface/upnp_ssdp_interval/upnp_max_age can lead to command injection. The attack can be executed remotely. The vendor was contacted early about this disclosure but did not respond in any way.

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-2026-2548?


## How do I fix CVE-2026-2548?

No fix has been published for CVE-2026-2548 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-2548 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2548 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-2548 and fix it if it is affected.

What it is: CVE-2026-2548 is a medium-severity command injection vulnerability in WAYOS FBM-220G, published on 16 Feb 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-2026-2548 exists.

Affected product: WAYOS FBM-220G. 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-2026-2548/ (Markdown: https://insights.sbomify.com/CVE-2026-2548/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-2548
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2548
- OSV: https://osv.dev/vulnerability/CVE-2026-2548

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-2548/
Summaries are generated and may contain mistakes; the official description above is the record.