# CVE-2026-101038: FAST FAC1200R MmtAtePrase stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in the MmtAtePrase function of FAST FAC1200R devices, potentially leading to code execution or denial of service.

- **Severity:** Critical 9.4 (`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`)
- **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:** 28 Sep 2026
- **Updated:** 28 Sep 2026
- **Also known as:** GHSA-49h3-g5vf-r66w

## What is CVE-2026-101038?

CVE-2026-101038 is a critical memory corruption vulnerability in FAST FAC1200R, published on 28 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability was determined in FAST FAC1200R 5.0_20201119_1.0.2. Affected by this vulnerability is the function MmtAtePrase of the component MmtAtePrase Parser. This manipulation causes stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-101038?


## How do I fix CVE-2026-101038?

No fix has been published for CVE-2026-101038 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101038 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101038 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101038 and fix it if it is affected.

What it is: CVE-2026-101038 is a critical memory corruption vulnerability in FAST FAC1200R, published on 28 Sep 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-2026-101038 exists.

Affected product: FAST FAC1200R. 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-2026-101038/ (Markdown: https://insights.sbomify.com/CVE-2026-101038/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101038
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101038
- OSV: https://osv.dev/vulnerability/CVE-2026-101038

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101038/
Summaries are generated and may contain mistakes; the official description above is the record.