# CVE-2021-4253: ctrlo lenio Ticket Lenio.pm cross site scripting

> Remote attackers can inject malicious scripts via the site_id argument in the Lenio ticket handler, requiring a patch to mitigate.

- **Severity:** Low 3.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N`)
- **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:** 18 Dec 2022
- **Updated:** 15 Apr 2025
- **Also known as:** GHSA-qqw2-fgff-h6h4

## What is CVE-2021-4253?

CVE-2021-4253 is a low-severity cross-site scripting vulnerability in ctrlo lenio, published on 18 Dec 2022. 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 vulnerability, which was classified as problematic, was found in ctrlo lenio. Affected is an unknown function in the library lib/Lenio.pm of the component Ticket Handler. The manipulation of the argument site_id leads to cross site scripting. It is possible to launch the attack remotely. The name of the patch is 7a1f90bd2a0ce95b8338ec0926902da975ec64d9. It is recommended to apply a patch to fix this issue. VDB-216210 is the identifier assigned to this vulnerability.

Weakness: CWE-707 (Improper Neutralization)

## Which versions are affected by CVE-2021-4253?

It affects 1 product.


Products: Ctrlo Lenio.

## How do I fix CVE-2021-4253?

No fix has been published for CVE-2021-4253 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4253 being exploited?

There is no known exploitation of CVE-2021-4253 in the wild and no public exploit code.

## Other vulnerabilities in ctrlo lenio

- [CVE-2021-4254](https://insights.sbomify.com/CVE-2021-4254/): ctrlo lenio Notice main.tt cross site scripting (low 3.5)
- [CVE-2021-4255](https://insights.sbomify.com/CVE-2021-4255/): ctrlo lenio contractor.tt cross site scripting (low 3.5)
- [CVE-2021-4256](https://insights.sbomify.com/CVE-2021-4256/): ctrlo lenio index.tt cross site scripting (low 3.5)
- [CVE-2021-4257](https://insights.sbomify.com/CVE-2021-4257/): ctrlo lenio Task task.tt cross site scripting (low 3.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4253 and fix it if it is affected.

What it is: CVE-2021-4253 is a low-severity cross-site scripting vulnerability in ctrlo lenio, published on 18 Dec 2022. 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-2021-4253 in the wild and no public exploit code.

Affected product: ctrlo lenio. 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-2021-4253/ (Markdown: https://insights.sbomify.com/CVE-2021-4253/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4253
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4253
- OSV: https://osv.dev/vulnerability/CVE-2021-4253

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4253/
Summaries are generated and may contain mistakes; the official description above is the record.