# CVE-2026-25789: Cross-site scripting in SIMATIC Drive Controller CPU 1504D TF

> Remote attackers can execute malicious JavaScript via crafted filenames on the firmware update page, leading to session hijacking or credential theft.

- **Severity:** High 7.2 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:L/VI:H/VA:H/SC:L/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 May 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-r662-c7v7-m9h4

## What is CVE-2026-25789?

CVE-2026-25789 is a high-severity cross-site scripting vulnerability in Siemens SIMATIC Drive Controller CPU 1504D TF, published on 12 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Affected devices do not properly validate and sanitize filenames on the Firmware Update page. This could allow a remote  attacker to social engineer the user into selecting the modified firmware file to be uploaded. This would result in malitcious JavaScript execution in the context of the authenticated user's session without requiring the file to be uploaded, potentially leading to session hijacking or credential theft.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-25789?


## How do I fix CVE-2026-25789?

No fix has been published for CVE-2026-25789 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-25789 being exploited?

There is no known exploitation of CVE-2026-25789 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25789 and fix it if it is affected.

What it is: CVE-2026-25789 is a high-severity cross-site scripting vulnerability in Siemens SIMATIC Drive Controller CPU 1504D TF, published on 12 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-25789 in the wild and no public exploit code.

Affected product: Siemens SIMATIC Drive Controller CPU 1504D TF. 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-2026-25789/ (Markdown: https://insights.sbomify.com/CVE-2026-25789/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25789
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25789
- OSV: https://osv.dev/vulnerability/CVE-2026-25789

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25789/
Summaries are generated and may contain mistakes; the official description above is the record.