# CVE-1999-1043: Denial of service in n/a

> Remote attackers can cause a denial of service in Microsoft Exchange Server by sending malformed NNTP or SMTP data.

- **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-hjv9-q8gw-pmgm

## What is CVE-1999-1043?

CVE-1999-1043 is a medium-severity denial of service vulnerability in Microsoft Exchange Server, 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 Exchange Server 5.5 and 5.0 does not properly handle (1) malformed NNTP data, or (2) malformed SMTP data, which allows remote attackers to cause a denial of service (application error).

## Which versions are affected by CVE-1999-1043?

It affects 1 product.


Products: Microsoft Exchange Server.

## How do I fix CVE-1999-1043?

No fix has been published for CVE-1999-1043 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-1043 being exploited?

There is no known exploitation of CVE-1999-1043 in the wild and no public exploit code.

## Other vulnerabilities in Microsoft Exchange Server

- [CVE-2024-21410](https://insights.sbomify.com/CVE-2024-21410/): Microsoft Exchange Server Privilege Escalation (critical 9.8, exploited in the wild)
- [CVE-2021-34473](https://insights.sbomify.com/CVE-2021-34473/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-26855](https://insights.sbomify.com/CVE-2021-26855/): Microsoft Exchange Server Remote Code Execution (critical 9.1, exploited in the wild)
- [CVE-2021-34523](https://insights.sbomify.com/CVE-2021-34523/): Microsoft Exchange Server Privilege Escalation (critical 9.0, exploited in the wild)
- [CVE-2023-21529](https://insights.sbomify.com/CVE-2023-21529/): Microsoft Exchange Server Deserialization of Untrusted Data (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-1043 and fix it if it is affected.

What it is: CVE-1999-1043 is a medium-severity denial of service vulnerability in Microsoft Exchange Server, 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-1999-1043 in the wild and no public exploit code.

Affected product: Microsoft Exchange Server. 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-1999-1043/ (Markdown: https://insights.sbomify.com/CVE-1999-1043/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-1043
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-1043
- OSV: https://osv.dev/vulnerability/CVE-1999-1043

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-1043/
Summaries are generated and may contain mistakes; the official description above is the record.