# CVE-2023-22915: Memory corruption in USG FLEX 50(W) firmware

> Remote unauthenticated attackers can cause denial of service via crafted HTTP requests if Facebook WiFi is enabled on affected Zyxel USG and VPN devices.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Apr 2023
- **Updated:** 12 Feb 2025
- **Also known as:** GHSA-qm4q-mvq2-gj2r

## What is CVE-2023-22915?

CVE-2023-22915 is a high-severity memory corruption vulnerability in Zyxel USG FLEX 50(W) firmware, published on 24 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A buffer overflow vulnerability in the “fbwifi_forward.cgi” CGI program of Zyxel USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.30 through 5.35, USG20(W)-VPN firmware versions 4.30 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow a remote unauthenticated attacker to cause DoS conditions by sending a crafted HTTP request if the Facebook WiFi function were enabled on an affected device.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2023-22915?

It affects 12 products.


Products: Zyxel Usg 20w-Vpn Firmware, Zyxel Usg Flex 100 Firmware, Zyxel Usg Flex 100w Firmware, Zyxel Usg Flex 200 Firmware, Zyxel Usg Flex 500 Firmware, Zyxel Usg Flex 50 Firmware, Zyxel Usg Flex 50w Firmware, Zyxel Usg Flex 700 Firmware, Zyxel Vpn1000 Firmware, Zyxel Vpn100 Firmware, Zyxel Vpn300 Firmware, Zyxel Vpn50 Firmware.

## How do I fix CVE-2023-22915?

No fix has been published for CVE-2023-22915 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-22915 being exploited?

There is no known exploitation of CVE-2023-22915 in the wild and no public exploit code.

## Other vulnerabilities in Zyxel USG FLEX 50(W) firmware

- [CVE-2023-28767](https://insights.sbomify.com/CVE-2023-28767/): Command injection in ATP series firmware (high 8.8)
- [CVE-2023-33011](https://insights.sbomify.com/CVE-2023-33011/): Command injection in ATP series firmware (high 8.8)
- [CVE-2023-33012](https://insights.sbomify.com/CVE-2023-33012/): Command injection in ATP series firmware (high 8.8)
- [CVE-2023-34138](https://insights.sbomify.com/CVE-2023-34138/): Command injection in ATP series firmware (high 8.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-22915 and fix it if it is affected.

What it is: CVE-2023-22915 is a high-severity memory corruption vulnerability in Zyxel USG FLEX 50(W) firmware, published on 24 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-22915 in the wild and no public exploit code.

Affected product: Zyxel USG FLEX 50(W) firmware. 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-2023-22915/ (Markdown: https://insights.sbomify.com/CVE-2023-22915/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-22915
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-22915
- OSV: https://osv.dev/vulnerability/CVE-2023-22915

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-22915/
Summaries are generated and may contain mistakes; the official description above is the record.