# CVE-2021-33425: Cross-site scripting in n/a

> Attackers can inject arbitrary JavaScript via the hostname field in OpenWRT LuCI, potentially executing code in the admin interface.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/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:** 25 May 2021
- **Updated:** 9 Jul 2026
- **Also known as:** GHSA-c35r-9rpc-98gc

## What is CVE-2021-33425?

CVE-2021-33425 is a medium-severity cross-site scripting vulnerability in Openwrt Openwrt, published on 25 May 2021. 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 (XSS) vulnerability was discovered in the Web Interface for OpenWRT LuCI version 19.07 which allows attackers to inject arbitrary Javascript in the OpenWRT Hostname via the Hostname Change operation.

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

## Which versions are affected by CVE-2021-33425?

It affects 1 product.


Products: Openwrt Openwrt.

## How do I fix CVE-2021-33425?

No fix has been published for CVE-2021-33425 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-33425 being exploited?

There is no known exploitation of CVE-2021-33425 in the wild and no public exploit code.

## Other vulnerabilities in Openwrt Openwrt

- [CVE-2020-28951](https://insights.sbomify.com/CVE-2020-28951/): Use after free in n/a (critical 9.8)
- [CVE-2026-62948](https://insights.sbomify.com/CVE-2026-62948/): Cross-site scripting in openwrt (critical 9.6)
- [CVE-2026-30871](https://insights.sbomify.com/CVE-2026-30871/): OpenWrt Project has Stack-based Buffer Overflow in DNS PTR Query (critical 9.5)
- [CVE-2026-30872](https://insights.sbomify.com/CVE-2026-30872/): OpenWrt Project has a Stack-based Buffer Overflow vulnerability via IPv6 reverse DNS lookup (critical 9.5)
- [CVE-2021-28961](https://insights.sbomify.com/CVE-2021-28961/): Command injection in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-33425 and fix it if it is affected.

What it is: CVE-2021-33425 is a medium-severity cross-site scripting vulnerability in Openwrt Openwrt, published on 25 May 2021. 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-2021-33425 in the wild and no public exploit code.

Affected product: Openwrt Openwrt. 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-2021-33425/ (Markdown: https://insights.sbomify.com/CVE-2021-33425/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33425
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33425
- OSV: https://osv.dev/vulnerability/CVE-2021-33425

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-33425/
Summaries are generated and may contain mistakes; the official description above is the record.