# CVE-2025-7673: Memory corruption in VMG8825-T50K firmware

> Unauthenticated attackers can cause denial of service or execute arbitrary code via a buffer overflow in the Zyxel VMG8825-T50K web server URL parser.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 16 Jul 2025
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-r3pp-h225-m34v

## What is CVE-2025-7673?

CVE-2025-7673 is a critical memory corruption vulnerability in Zyxel VMG8825-T50K firmware, published on 16 Jul 2025. 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 URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

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

## Which versions are affected by CVE-2025-7673?

It affects 24 products.


Products: Zyxel Emg3525-T50b Firmware, Zyxel Emg5523-T50b Firmware, Zyxel Emg5723-T50k Firmware, Zyxel Emg6726-B10a Firmware, Zyxel Ex3510-B0 Firmware, Zyxel Ex5510-B0 Firmware, Zyxel Vmg1312-T20b Firmware, Zyxel Vmg3625-T50b Firmware, Zyxel Vmg3925-B10b Firmware, Zyxel Vmg3925-B10c Firmware, Zyxel Vmg3927-B50a Firmware, Zyxel Vmg3927-B50b Firmware, Zyxel Vmg3927-B60a Firmware, Zyxel Vmg3927-T50k Firmware, Zyxel Vmg4005-B50b Firmware, Zyxel Vmg4927-B50a Firmware, Zyxel Vmg8623-T50b Firmware, Zyxel Vmg8825-B50a Firmware, Zyxel Vmg8825-B60a Firmware, Zyxel Vmg8825-Bx0b Firmware and 4 more.

## How do I fix CVE-2025-7673?

No fix has been published for CVE-2025-7673 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-7673 being exploited?

There is no known exploitation of CVE-2025-7673 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-7673 and fix it if it is affected.

What it is: CVE-2025-7673 is a critical memory corruption vulnerability in Zyxel VMG8825-T50K firmware, published on 16 Jul 2025. 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-2025-7673 in the wild and no public exploit code.

Affected product: Zyxel VMG8825-T50K 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-2025-7673/ (Markdown: https://insights.sbomify.com/CVE-2025-7673/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-7673
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-7673
- OSV: https://osv.dev/vulnerability/CVE-2025-7673

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-7673/
Summaries are generated and may contain mistakes; the official description above is the record.