# CVE-2020-19049: Cross-site scripting in n/a

> Remote attackers can inject arbitrary web script or HTML via the forum description field in MyBB, potentially leading to session hijacking or malicious actions.

- **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:** 31 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** BIT-mybb-2020-19049, GHSA-x5c3-9c32-978j

## What is CVE-2020-19049?

CVE-2020-19049 is a medium-severity cross-site scripting vulnerability in Mybb Mybb, published on 31 Aug 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

Cross Site Scripting (XSS) in MyBB v1.8.20 allows remote attackers to inject arbitrary web script or HTML via the "Description" field found in the "Add New Forum" page by doing an authenticated POST HTTP request to '/Upload/admin/index.php?module=forum-management&action=add'.

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

## Which versions are affected by CVE-2020-19049?

1 open source package ship an affected version, including mybb. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `mybb` | Bitnami | From 1.8.20 to 1.8.20 | None |

Products: Mybb Mybb.

## How do I fix CVE-2020-19049?

No fix has been published for CVE-2020-19049 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-19049 being exploited?

There is no known exploitation of CVE-2020-19049 in the wild and no public exploit code.

## Other vulnerabilities in Mybb Mybb

- [CVE-2011-10018](https://insights.sbomify.com/CVE-2011-10018/): myBB 1.6.4 Backdoor Arbitrary Command Execution (critical 10.0)
- [CVE-2015-2786](https://insights.sbomify.com/CVE-2015-2786/): Information disclosure in n/a (critical 10.0)
- [CVE-2011-5133](https://insights.sbomify.com/CVE-2011-5133/): Cross-site scripting in n/a (critical 10.0)
- [CVE-2006-0218](https://insights.sbomify.com/CVE-2006-0218/): SQL injection in n/a (critical 10.0)
- [CVE-2020-22612](https://insights.sbomify.com/CVE-2020-22612/): Code injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-19049 and fix it if it is affected.

What it is: CVE-2020-19049 is a medium-severity cross-site scripting vulnerability in Mybb Mybb, published on 31 Aug 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-2020-19049 in the wild and no public exploit code.

Affected packages and fixed versions:
- mybb (Bitnami): affected from 1.8.20 up to 1.8.20; no fix listed

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-2020-19049/ (Markdown: https://insights.sbomify.com/CVE-2020-19049/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-19049
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-19049
- OSV: https://osv.dev/vulnerability/CVE-2020-19049

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-19049/
Summaries are generated and may contain mistakes; the official description above is the record.