# CVE-2017-16944: Denial of service in n/a

> Remote attackers can cause a denial of service in Exim via infinite loop and stack exhaustion using BDAT commands.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Nov 2017
- **Updated:** 5 Aug 2024
- **Also known as:** CLEANSTART-2025-UI48931, DEBIAN-CVE-2017-16944, GHSA-vpr2-5gxq-hjc6

## What is CVE-2017-16944?

CVE-2017-16944 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 25 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to cause a denial of service (infinite loop and stack exhaustion) via vectors involving BDAT commands and an improper check for a '.' character signifying the end of the content, related to the bdat_getc function.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2017-16944?

It affects 2 products.


Products: Debian Debian Linux, Exim Exim.

## How do I fix CVE-2017-16944?

Apply the vendor's patch.

## Is CVE-2017-16944 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-16944 exists.

Public exploit code:

- Exim 4.89 - 'BDAT' Denial of Service (exploitdb)

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-16944 and fix it if it is affected.

What it is: CVE-2017-16944 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 25 Nov 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-16944 exists.

Affected product: Debian Debian Linux. 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-2017-16944/ (Markdown: https://insights.sbomify.com/CVE-2017-16944/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-16944
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-16944
- OSV: https://osv.dev/vulnerability/CVE-2017-16944

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-16944/
Summaries are generated and may contain mistakes; the official description above is the record.