# CVE-2021-45904: Cross-site scripting in n/a

> An attacker can inject malicious scripts via the Port Forwards Add Name screen in OpenWrt, potentially compromising user sessions.

- **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:** 27 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-phgx-qrq5-mx9m

## What is CVE-2021-45904?

CVE-2021-45904 is a medium-severity cross-site scripting vulnerability in Openwrt Openwrt, published on 27 Dec 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

OpenWrt 21.02.1 allows XSS via the Port Forwards Add Name screen.

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

## Which versions are affected by CVE-2021-45904?

It affects 1 product.


Products: Openwrt Openwrt.

## How do I fix CVE-2021-45904?

No fix has been published for CVE-2021-45904 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-45904 being exploited?

There is no known exploitation of CVE-2021-45904 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-2021-45904 and fix it if it is affected.

What it is: CVE-2021-45904 is a medium-severity cross-site scripting vulnerability in Openwrt Openwrt, published on 27 Dec 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-2021-45904 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-2021-45904/ (Markdown: https://insights.sbomify.com/CVE-2021-45904/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45904
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45904
- OSV: https://osv.dev/vulnerability/CVE-2021-45904

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45904/
Summaries are generated and may contain mistakes; the official description above is the record.