# CVE-2026-61399: Apache CloudStack: Cross-Site Scripting (XSS) Vulnerability in Lock User Function in UI

> Attackers can execute arbitrary scripts in the CloudStack UI via the Lock User function, potentially compromising user accounts.

- **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 21 Aug 2026
- **Updated:** 24 Aug 2026
- **Also known as:** GHSA-4rrq-73x5-wj26

## What is CVE-2026-61399?

CVE-2026-61399 is a medium-severity cross-site scripting vulnerability in Apache Cloudstack, published on 21 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

Improper Encoding or Escaping of Output vulnerability in Apache CloudStack's UI while using Lock User Functionality.

This issue affects Apache CloudStack: from 4.20.0.0 through 4.20.3.0 and from 4.21.0.0 through 4.22.1.0.

Users are recommended to upgrade to version 4.20.3.1 or 4.22.1.1 or later, which fixes the issue.

Weakness: CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-61399?

It affects 1 product.


Products: Apache Cloudstack.

## How do I fix CVE-2026-61399?

No fix has been published for CVE-2026-61399 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-61399 being exploited?

There is no known exploitation of CVE-2026-61399 in the wild and no public exploit code.

## Other vulnerabilities in Apache Cloudstack

- [CVE-2012-4501](https://insights.sbomify.com/CVE-2012-4501/): Missing authorization in n/a (critical 10.0)
- [CVE-2024-38346](https://insights.sbomify.com/CVE-2024-38346/): Apache CloudStack: Unauthenticated cluster service port leads to remote execution (critical 9.8)
- [CVE-2024-39864](https://insights.sbomify.com/CVE-2024-39864/): Apache CloudStack: Integration API service uses dynamic port when disabled (critical 9.8)
- [CVE-2024-29006](https://insights.sbomify.com/CVE-2024-29006/): Apache CloudStack: x-forwarded-for HTTP header parsed by default (critical 9.8)
- [CVE-2022-35741](https://insights.sbomify.com/CVE-2022-35741/): Apache CloudStack SAML Single Sign-On XXE (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61399 and fix it if it is affected.

What it is: CVE-2026-61399 is a medium-severity cross-site scripting vulnerability in Apache Cloudstack, published on 21 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-61399 in the wild and no public exploit code.

Affected product: Apache Cloudstack. 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-2026-61399/ (Markdown: https://insights.sbomify.com/CVE-2026-61399/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61399
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61399
- OSV: https://osv.dev/vulnerability/CVE-2026-61399

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61399/
Summaries are generated and may contain mistakes; the official description above is the record.