# CVE-2020-8291: Cross-site scripting in Rocket.Chat server

> Attackers can execute arbitrary scripts in user browsers via link preview rendering, potentially leading to account takeover.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 18 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-5vc2-xx2f-qhg3

## What is CVE-2020-8291?

CVE-2020-8291 is a medium-severity cross-site scripting vulnerability in Rocket.chat Rocket.chat, published on 18 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A link preview rendering issue in Rocket.Chat versions before 3.9 could lead to potential XSS attacks.

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

## Which versions are affected by CVE-2020-8291?

It affects 1 product.


Products: Rocket.chat Rocket.chat.

## How do I fix CVE-2020-8291?

No fix has been published for CVE-2020-8291 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-8291 being exploited?

There is no known exploitation of CVE-2020-8291 in the wild and no public exploit code.

## Other vulnerabilities in Rocket.chat Rocket.chat

- [CVE-2026-58066](https://insights.sbomify.com/CVE-2026-58066/): Auth bypass in Rocket.Chat (critical 9.8)
- [CVE-2026-29198](https://insights.sbomify.com/CVE-2026-29198/): SQL injection in Rocket.Chat (critical 9.8)
- [CVE-2023-28316](https://insights.sbomify.com/CVE-2023-28316/): Security feature bypass in Rocket.Chat (critical 9.8)
- [CVE-2022-44567](https://insights.sbomify.com/CVE-2022-44567/): Command injection in Rocket.chat - Electron Desktop (critical 9.8)
- [CVE-2021-22910](https://insights.sbomify.com/CVE-2021-22910/): Code injection in Rocket.Chat server (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8291 and fix it if it is affected.

What it is: CVE-2020-8291 is a medium-severity cross-site scripting vulnerability in Rocket.chat Rocket.chat, published on 18 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-8291 in the wild and no public exploit code.

Affected product: Rocket.chat Rocket.chat. 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-2020-8291/ (Markdown: https://insights.sbomify.com/CVE-2020-8291/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8291
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8291
- OSV: https://osv.dev/vulnerability/CVE-2020-8291

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8291/
Summaries are generated and may contain mistakes; the official description above is the record.