# CVE-2021-45100: Weak cryptography in n/a

> The ksmbd server incorrectly handles SMB encryption flags, causing Windows clients to disable encryption and transmit data in cleartext.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:** 16 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-45100, GHSA-2872-89wh-3frc, UBUNTU-CVE-2021-45100

## What is CVE-2021-45100?

CVE-2021-45100 is a high-severity vulnerability in Netapp H300e Firmware, published on 16 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ksmbd server through 3.4.2, as used in the Linux kernel through 5.15.8, sometimes communicates in cleartext even though encryption has been enabled. This occurs because it sets the SMB2_GLOBAL_CAP_ENCRYPTION flag when using the SMB 3.1.1 protocol, which is a violation of the SMB protocol specification. When Windows 10 detects this protocol violation, it disables encryption.

Weakness: CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2021-45100?

It affects 9 products.


Products: Ksmbd Project Ksmbd, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware.

## How do I fix CVE-2021-45100?

Apply the vendor's patch.

## Is CVE-2021-45100 being exploited?

There is no known exploitation of CVE-2021-45100 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-45100 and fix it if it is affected.

What it is: CVE-2021-45100 is a high-severity vulnerability in Netapp H300e Firmware, published on 16 Dec 2021. 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-2021-45100 in the wild and no public exploit code.

Affected product: Netapp H300e Firmware. 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-2021-45100/ (Markdown: https://insights.sbomify.com/CVE-2021-45100/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45100
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45100
- OSV: https://osv.dev/vulnerability/CVE-2021-45100

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45100/
Summaries are generated and may contain mistakes; the official description above is the record.