# CVE-2025-46171: Denial of service in n/a

> An authenticated user can crash the vBulletin forum by triggering excessive memory consumption through a large buddy list.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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:** 23 Jul 2025
- **Updated:** 5 Jul 2026
- **Also known as:** GHSA-q9rx-45gj-g3f5

## What is CVE-2025-46171?

CVE-2025-46171 is a medium-severity denial of service vulnerability in Vbulletin Vbulletin, published on 23 Jul 2025. 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

vBulletin 3.8.7 is vulnerable to a denial-of-service condition via the misc.php?do=buddylist endpoint. If an authenticated user has a sufficiently large buddy list, processing the list can consume excessive memory, exhausting system resources and crashing the forum.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2025-46171?

It affects 1 product.


Products: Vbulletin Vbulletin.

## How do I fix CVE-2025-46171?

No fix has been published for CVE-2025-46171 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-46171 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-46171 exists.

Public exploit code:

- Writeup of a Denial of Service vulnerability in the vBulletin 3.8.7 friends list. (github_poc): https://github.com/oiyl/CVE-2025-46171

## Other vulnerabilities in Vbulletin Vbulletin

- [CVE-2020-17496](https://insights.sbomify.com/CVE-2020-17496/): vBulletin PHP Module Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16759](https://insights.sbomify.com/CVE-2019-16759/): vBulletin PHP Module Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2025-48827](https://insights.sbomify.com/CVE-2025-48827/): vBulletin 5.0.0 through 5.7.5 and 6.0.0 through 6.0.3 allows unauthenticated users to invoke protected API controllers' methods when running (critical 10.0)
- [CVE-2023-25135](https://insights.sbomify.com/CVE-2023-25135/): Deserialization in n/a (critical 9.8)
- [CVE-2020-7373](https://insights.sbomify.com/CVE-2020-7373/): Code injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-46171 and fix it if it is affected.

What it is: CVE-2025-46171 is a medium-severity denial of service vulnerability in Vbulletin Vbulletin, published on 23 Jul 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-46171 exists.

Affected product: Vbulletin Vbulletin. 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-2025-46171/ (Markdown: https://insights.sbomify.com/CVE-2025-46171/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-46171
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-46171
- OSV: https://osv.dev/vulnerability/CVE-2025-46171

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-46171/
Summaries are generated and may contain mistakes; the official description above is the record.