# CVE-2023-34461: Cross-site Scripting (XSS) Availability in PyBB

> Attackers with posting privileges can inject malicious HTML/JavaScript into PyBB posts, leading to client-side code execution.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/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:** 19 Jun 2023
- **Updated:** 9 Dec 2024

## What is CVE-2023-34461?

CVE-2023-34461 is a medium-severity cross-site scripting vulnerability in benjjvi PyBB, published on 19 Jun 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

PyBB is an open source bulletin board. A manual code review of the PyBB bulletin board server has revealed that a vulnerability could have been exploited in which users could submit any type of HTML tag, and have said tag run. For example, a malicious `<a>` that looks like ```<a href=javascript:alert (1)>xss</a>``` could have been used to run code through JavaScript on the client side. The problem has been patched as of commit `5defd92`, and users are advised to upgrade. Attackers do need posting privilege in order to exploit this vulnerability. This vulnerability is present within the 0.1.0 release, and users are advised to upgrade to 0.1.1. Users unable to upgrade may be able to work around the attack by either; Removing the ability to create posts, removing the `|safe` tag from the Jinja2 template titled "post.html" in templates or by adding manual validation of links in the post creation section.

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

## Which versions are affected by CVE-2023-34461?

It affects 1 product.


Products: Pybb Project Pybb.

## How do I fix CVE-2023-34461?

No fix has been published for CVE-2023-34461 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-34461 being exploited?

There is no known exploitation of CVE-2023-34461 in the wild and no public exploit code.

## Other vulnerabilities in benjjvi PyBB

- [CVE-2023-34249](https://insights.sbomify.com/CVE-2023-34249/): benjjvi/PyBB may send unsanitized request to SQL database (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-34461 and fix it if it is affected.

What it is: CVE-2023-34461 is a medium-severity cross-site scripting vulnerability in benjjvi PyBB, published on 19 Jun 2023. 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-2023-34461 in the wild and no public exploit code.

Affected product: benjjvi PyBB. 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-2023-34461/ (Markdown: https://insights.sbomify.com/CVE-2023-34461/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-34461
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-34461
- OSV: https://osv.dev/vulnerability/CVE-2023-34461

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-34461/
Summaries are generated and may contain mistakes; the official description above is the record.