# CVE-2026-69646: Skype for Business Spoofing Vulnerability

> An attacker can spoof communications in Skype for Business Server by bypassing cryptographic signature verification over an adjacent network.

- **Severity:** High 8.3 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Sep 2026
- **Updated:** 14 Oct 2026
- **Also known as:** GHSA-935c-p9xv-m74w

## What is CVE-2026-69646?

CVE-2026-69646 is a high-severity vulnerability in Microsoft Skype for Business Server 2015 CU13, published on 8 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Improper verification of cryptographic signature in Skype for Business allows an unauthorized attacker to perform spoofing over an adjacent network.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-69646?

It affects 2 products.


Products: Microsoft Skype for Business Server, Microsoft Skype for Business Server Subscription Edition.

## How do I fix CVE-2026-69646?

No fix has been published for CVE-2026-69646 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-69646 being exploited?

There is no known exploitation of CVE-2026-69646 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Skype for Business Server 2015 CU13

- [CVE-2023-41763](https://insights.sbomify.com/CVE-2023-41763/): Microsoft Skype for Business Privilege Escalation (medium 5.3, exploited in the wild)
- [CVE-2026-66302](https://insights.sbomify.com/CVE-2026-66302/): Skype for Business Remote Code Execution Vulnerability (critical 9.8)
- [CVE-2026-66304](https://insights.sbomify.com/CVE-2026-66304/): Skype for Business Information Disclosure Vulnerability (high 7.5)
- [CVE-2026-66307](https://insights.sbomify.com/CVE-2026-66307/): Skype for Business and Lync Denial of Service Vulnerability (high 7.5)
- [CVE-2023-36780](https://insights.sbomify.com/CVE-2023-36780/): Skype for Business Remote Code Execution Vulnerability (high 7.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-69646 and fix it if it is affected.

What it is: CVE-2026-69646 is a high-severity vulnerability in Microsoft Skype for Business Server 2015 CU13, published on 8 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-69646 in the wild and no public exploit code.

Affected product: Microsoft Skype for Business Server 2015 CU13. 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-2026-69646/ (Markdown: https://insights.sbomify.com/CVE-2026-69646/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-69646
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-69646
- OSV: https://osv.dev/vulnerability/CVE-2026-69646

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-69646/
Summaries are generated and may contain mistakes; the official description above is the record.