# CVE-2018-8311: Code injection in Microsoft Lync

> Attackers can execute arbitrary code remotely by sending specially crafted content to Skype for Business or Lync clients.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **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:** 11 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-v5v7-qp5p-hxjg

## What is CVE-2018-8311?

CVE-2018-8311 is a high-severity code injection vulnerability in Microsoft Lync, published on 11 Jul 2018. 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

A remote code execution vulnerability exists when Skype for Business and Microsoft Lync clients fail to properly sanitize specially crafted content, aka "Remote Code Execution Vulnerability in Skype For Business and Lync." This affects Skype, Microsoft Lync.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-8311?

It affects 2 products.


Products: Microsoft Lync, Microsoft Skype for Business.

## How do I fix CVE-2018-8311?

No fix has been published for CVE-2018-8311 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-8311 being exploited?

There is no known exploitation of CVE-2018-8311 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Lync

- [CVE-2020-1025](https://insights.sbomify.com/CVE-2020-1025/): Microsoft Office Elevation of Privilege Vulnerability (critical 9.8)
- [CVE-2013-1302](https://insights.sbomify.com/CVE-2013-1302/): Use after free in n/a (critical 9.3)
- [CVE-2012-1849](https://insights.sbomify.com/CVE-2012-1849/): Path traversal in n/a (critical 9.3)
- [CVE-2017-11786](https://insights.sbomify.com/CVE-2017-11786/): Auth bypass in Skype for Business (high 8.8)
- [CVE-2017-0283](https://insights.sbomify.com/CVE-2017-0283/): Memory corruption in Uniscribe (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-8311 and fix it if it is affected.

What it is: CVE-2018-8311 is a high-severity code injection vulnerability in Microsoft Lync, published on 11 Jul 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-8311 in the wild and no public exploit code.

Affected product: Microsoft Lync. 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-2018-8311/ (Markdown: https://insights.sbomify.com/CVE-2018-8311/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-8311
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-8311
- OSV: https://osv.dev/vulnerability/CVE-2018-8311

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-8311/
Summaries are generated and may contain mistakes; the official description above is the record.