# CVE-1999-1164: Denial of service in n/a

> Remote attackers can cause Microsoft Outlook to hang by sending multiple emails with identical X-UIDL headers, resulting in a denial of service.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Sep 2001
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-f498-r72q-hr69

## What is CVE-1999-1164?

CVE-1999-1164 is a medium-severity denial of service vulnerability in Microsoft Outlook, published on 12 Sep 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Microsoft Outlook client allows remote attackers to cause a denial of service by sending multiple email messages with the same X-UIDL headers, which causes Outlook to hang.

## Which versions are affected by CVE-1999-1164?

It affects 2 products.


Products: Microsoft Outlook, Microsoft Outlook Express.

## How do I fix CVE-1999-1164?

No fix has been published for CVE-1999-1164 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-1164 being exploited?

There is no known exploitation of CVE-1999-1164 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Outlook

- [CVE-2017-11774](https://insights.sbomify.com/CVE-2017-11774/): Microsoft Office Outlook Security Feature Bypass (high 7.8, exploited in the wild)
- [CVE-2001-0538](https://insights.sbomify.com/CVE-2001-0538/): Code injection in n/a (critical 10.0)
- [CVE-2013-3870](https://insights.sbomify.com/CVE-2013-3870/): Use after free in n/a (critical 9.3)
- [CVE-2010-2728](https://insights.sbomify.com/CVE-2010-2728/): Memory corruption in n/a (critical 9.3)
- [CVE-2010-0266](https://insights.sbomify.com/CVE-2010-0266/): Code injection in n/a (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-1164 and fix it if it is affected.

What it is: CVE-1999-1164 is a medium-severity denial of service vulnerability in Microsoft Outlook, published on 12 Sep 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-1999-1164 in the wild and no public exploit code.

Affected product: Microsoft Outlook. 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-1999-1164/ (Markdown: https://insights.sbomify.com/CVE-1999-1164/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-1164
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-1164
- OSV: https://osv.dev/vulnerability/CVE-1999-1164

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-1164/
Summaries are generated and may contain mistakes; the official description above is the record.