# CVE-2026-123391: Microsoft Office SharePoint Elevation of Privilege Vulnerability


- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 10 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-q5ph-8xwx-3hvh

## What is CVE-2026-123391?

CVE-2026-123391 is a high-severity vulnerability in Microsoft SharePoint Server Subscription Edition, published on 10 Nov 2026. 

### Official description

Incorrect authorization in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-123391?


## How do I fix CVE-2026-123391?

No fix has been published for CVE-2026-123391 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123391 being exploited?

There is no known exploitation of CVE-2026-123391 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123391 and fix it if it is affected.

What it is: CVE-2026-123391 is a high-severity vulnerability in Microsoft SharePoint Server Subscription Edition, published on 10 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123391 in the wild and no public exploit code.

Affected product: Microsoft SharePoint Server Subscription Edition. 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-2026-123391/ (Markdown: https://insights.sbomify.com/CVE-2026-123391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123391
- OSV: https://osv.dev/vulnerability/CVE-2026-123391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123391/
Summaries are generated and may contain mistakes; the official description above is the record.