# CVE-2025-40899: Stored Cross-Site Scripting (XSS) in Assets and Nodes in Guardian/CMC before 26.0.0

> Authenticated users can inject malicious scripts via custom fields, allowing attackers to execute code in victims' browsers to modify data or access information.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:H/VA:H/SC:L/SI:L/SA:L`)
- **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:** 15 Apr 2026
- **Updated:** 11 Aug 2026
- **Also known as:** GHSA-28p4-5j5m-924h

## What is CVE-2025-40899?

CVE-2025-40899 is a high-severity cross-site scripting vulnerability in Nozomi Networks CMC, published on 15 Apr 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

A Stored Cross-Site Scripting vulnerability was discovered in the Assets and Nodes functionality due to improper validation of an input parameter. An authenticated user with custom fields privileges can define a malicious custom field containing a JavaScript payload. When the victim views the Assets or Nodes pages, the XSS executes in their browser context, allowing the attacker to perform unauthorized actions as the victim, such as modify application data, disrupt application availability, and access limited sensitive information.

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

## Which versions are affected by CVE-2025-40899?


## How do I fix CVE-2025-40899?

No fix has been published for CVE-2025-40899 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-40899 being exploited?

There is no known exploitation of CVE-2025-40899 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40899 and fix it if it is affected.

What it is: CVE-2025-40899 is a high-severity cross-site scripting vulnerability in Nozomi Networks CMC, published on 15 Apr 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-2025-40899 in the wild and no public exploit code.

Affected product: Nozomi Networks CMC. 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-2025-40899/ (Markdown: https://insights.sbomify.com/CVE-2025-40899/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40899
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40899
- OSV: https://osv.dev/vulnerability/CVE-2025-40899

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40899/
Summaries are generated and may contain mistakes; the official description above is the record.