# CVE-2026-19061: Insta InstaKNXServiceApp Firmware Update CreateWebClientAndDownloadFileList data authenticity

> Alleged insufficient verification of firmware update authenticity in InstaKNXServiceApp, disputed by vendor as checks occur post-transfer.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Aug 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-v442-3w5q-c7m5

## What is CVE-2026-19061?

CVE-2026-19061 is a medium-severity vulnerability in InstaKNXServiceApp, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw has been found in Insta InstaKNXServiceApp 1.2.3.1469. Affected by this issue is the function CreateWebClientAndDownloadFileList of the component Firmware Update Handler. Executing a manipulation can lead to insufficient verification of data authenticity. It is possible to launch the attack remotely. Attacks of this nature are highly complex. The exploitation is known to be difficult. There are still doubts about whether this vulnerability truly exists. The vendor explains: "[T]he entry suggests that the device does not verify the authenticity of the update. This is incorrect. The device performs an authenticity check after the complete update has been transferred. If this check fails, the update is not installed and the previously installed firmware continues to run".

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-19061?


## How do I fix CVE-2026-19061?

No fix has been published for CVE-2026-19061 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-19061 being exploited?

There is no known exploitation of CVE-2026-19061 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19061 and fix it if it is affected.

What it is: CVE-2026-19061 is a medium-severity vulnerability in InstaKNXServiceApp, published on 6 Aug 2026. 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-2026-19061 in the wild and no public exploit code.

Affected product: InstaKNXServiceApp. 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-2026-19061/ (Markdown: https://insights.sbomify.com/CVE-2026-19061/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19061
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19061
- OSV: https://osv.dev/vulnerability/CVE-2026-19061

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-19061/
Summaries are generated and may contain mistakes; the official description above is the record.