# CVE-2021-27559: Cross-site scripting in n/a

> Attackers can inject malicious scripts via the Nickname field on the Contact page, potentially stealing user sessions or executing code.

- **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:** 22 Feb 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-2mm4-8fvv-52q9

## What is CVE-2021-27559?

CVE-2021-27559 is a medium-severity cross-site scripting vulnerability in n/a, published on 22 Feb 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

The Contact page in Monica 2.19.1 allows stored XSS via the Nickname field.

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

## Which versions are affected by CVE-2021-27559?

It affects 1 product.


Products: Monicahq Monica.

## How do I fix CVE-2021-27559?

No fix has been published for CVE-2021-27559 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27559 being exploited?

There is no known exploitation of CVE-2021-27559 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-26747](https://insights.sbomify.com/CVE-2026-26747/): Open redirect in n/a (critical 9.1)
- [CVE-2024-54996](https://insights.sbomify.com/CVE-2024-54996/): Cross-site scripting in n/a (high 8.8)
- [CVE-2023-1031](https://insights.sbomify.com/CVE-2023-1031/): Cross-site scripting in MonicaHQ (high 8.8)
- [CVE-2023-1094](https://insights.sbomify.com/CVE-2023-1094/): Code injection in MonicaHQ (high 8.0)
- [CVE-2024-54999](https://insights.sbomify.com/CVE-2024-54999/): Code injection in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27559 and fix it if it is affected.

What it is: CVE-2021-27559 is a medium-severity cross-site scripting vulnerability in n/a, published on 22 Feb 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-2021-27559 in the wild and no public exploit code.

Affected product: n/a. 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-2021-27559/ (Markdown: https://insights.sbomify.com/CVE-2021-27559/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27559
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27559
- OSV: https://osv.dev/vulnerability/CVE-2021-27559

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27559/
Summaries are generated and may contain mistakes; the official description above is the record.