# CVE-2017-12151: Security feature bypass in samba

> Samba clients using SMB3 with DFS redirects may lose encryption and signing requirements, allowing man-in-the-middle attackers to read or modify data.

- **Severity:** High 7.4 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2017-12151, DEBIAN-CVE-2017-12151, ECHO-3a2e-e8a7-a38b, GHSA-xc7p-hf9j-w53w, UBUNTU-CVE-2017-12151

## What is CVE-2017-12151?

CVE-2017-12151 is a high-severity vulnerability in Debian Debian Linux, published on 27 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in the way samba client before samba 4.4.16, samba 4.5.14 and samba 4.6.8 used encryption with the max protocol set as SMB3. The connection could lose the requirement for signing and encrypting to any DFS redirects, allowing an attacker to read or alter the contents of the connection via a man-in-the-middle attack.

Weakness: CWE-310, CWE-300 (Channel Accessible by Non-Endpoint)

## Which versions are affected by CVE-2017-12151?

It affects 8 products.


Products: Debian Debian Linux, Hp Cifs Server, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Workstation, Samba Samba.

## How do I fix CVE-2017-12151?

Upgrade to a fixed version.

## Is CVE-2017-12151 being exploited?

There is no known exploitation of CVE-2017-12151 in the wild and no public exploit code.

## 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-2017-12151 and fix it if it is affected.

What it is: CVE-2017-12151 is a high-severity vulnerability in Debian Debian Linux, published on 27 Jul 2018. 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-2017-12151 in the wild and no public exploit code.

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-2017-12151/ (Markdown: https://insights.sbomify.com/CVE-2017-12151/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12151
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12151
- OSV: https://osv.dev/vulnerability/CVE-2017-12151

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-12151/
Summaries are generated and may contain mistakes; the official description above is the record.