# CVE-2018-8426: Cross-site scripting in Microsoft SharePoint

> An attacker can execute arbitrary scripts in the context of a user's browser via a crafted request to Microsoft SharePoint.

- **Severity:** Medium 5.4 (`CVSS:3.0/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:** 13 Sep 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-87vw-7wf8-wpfx

## What is CVE-2018-8426?

CVE-2018-8426 is a medium-severity cross-site scripting vulnerability in Microsoft SharePoint, published on 13 Sep 2018. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

A cross-site-scripting (XSS) vulnerability exists when Microsoft SharePoint Server does not properly sanitize a specially crafted web request to an affected SharePoint server, aka "Microsoft Office SharePoint XSS Vulnerability." This affects Microsoft SharePoint Server, Microsoft SharePoint.

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

## Which versions are affected by CVE-2018-8426?

It affects 3 products.


Products: Microsoft Sharepoint Enterprise Server 2013, Microsoft Sharepoint Enterprise Server 2016, Microsoft Sharepoint Server 2010.

## How do I fix CVE-2018-8426?

No fix has been published for CVE-2018-8426 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-8426 being exploited?

There is no known exploitation of CVE-2018-8426 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-8426 and fix it if it is affected.

What it is: CVE-2018-8426 is a medium-severity cross-site scripting vulnerability in Microsoft SharePoint, published on 13 Sep 2018. 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-2018-8426 in the wild and no public exploit code.

Affected product: Microsoft SharePoint. 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-2018-8426/ (Markdown: https://insights.sbomify.com/CVE-2018-8426/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-8426
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-8426
- OSV: https://osv.dev/vulnerability/CVE-2018-8426

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From sbomify Insights: https://insights.sbomify.com/CVE-2018-8426/
Summaries are generated and may contain mistakes; the official description above is the record.