# CVE-2026-101354: FAST FAC1203R MmtAtePrase _tWlanTask stack-based overflow

> A stack-based buffer overflow in the MmtAtePrase parser allows local network attackers to execute arbitrary code on FAST FAC1203R routers.

- **Severity:** Critical 9.4 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-ccwh-mr5w-5j9f

## What is CVE-2026-101354?

CVE-2026-101354 is a critical memory corruption vulnerability in FAST FAC1203R, published on 29 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A security flaw has been discovered in FAST FAC1203R 20200116_2.0.4. The affected element is the function _tWlanTask of the component MmtAtePrase Parser. Performing a manipulation results in stack-based buffer overflow. The attacker must have access to the local network to execute the attack. The exploit has been released to the public and may be used for attacks. 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-2026-101354?


## How do I fix CVE-2026-101354?

No fix has been published for CVE-2026-101354 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101354 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101354 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101354 and fix it if it is affected.

What it is: CVE-2026-101354 is a critical memory corruption vulnerability in FAST FAC1203R, published on 29 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101354 exists.

Affected product: FAST FAC1203R. 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-2026-101354/ (Markdown: https://insights.sbomify.com/CVE-2026-101354/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101354
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101354
- OSV: https://osv.dev/vulnerability/CVE-2026-101354

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-101354/
Summaries are generated and may contain mistakes; the official description above is the record.