# CVE-2021-3565: Weak cryptography in tpm2-tools

> A fixed AES key in tpm2-tools allows MITM attackers to unwrap inner data and reveal imported keys, compromising confidentiality.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/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:** 4 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** ALSA-2021:4413, AZL-6923, DEBIAN-CVE-2021-3565, GHSA-jxhq-r9c5-f85p, MGASA-2021-0353, OESA-2021-1384, RHSA-2021:4413, RLSA-2021:4413, SUSE-SU-2021:1998-1, SUSE-SU-2021:1999-1, UBUNTU-CVE-2021-3565, openSUSE-SU-2021:0934-1, openSUSE-SU-2021:1998-1

## What is CVE-2021-3565?

CVE-2021-3565 is a medium-severity vulnerability in Fedoraproject Fedora, published on 4 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in tpm2-tools in versions before 5.1.1 and before 4.3.2. tpm2_import used a fixed AES key for the inner wrapper, potentially allowing a MITM attacker to unwrap the inner portion and reveal the key being imported. The highest threat from this vulnerability is to data confidentiality.

Weakness: CWE-798 (Use of Hard-coded Credentials), CWE-665 (Improper Initialization)

## Which versions are affected by CVE-2021-3565?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tpm2-tools` | AlmaLinux:8 | All versions | 4.1.1-5.el8 |
| `tpm2-tools` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.1.1-5.el8 |
| `tpm2-tools-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.1.1-5.el8 |
| `tpm2-tools-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.1.1-5.el8 |
| `tpm2-tools` | Rocky Linux:8 | All versions | 0:4.1.1-5.el8 |
| `tpm2.0-tools` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 4.1-3.3.1 |
| `tpm2.0-tools` | SUSE:Linux Enterprise Module for Basesystem 15 SP3 | All versions | 4.3.0-4.3.1 |
| `tpm2.0-tools` | openSUSE:Leap 15.2 | All versions | 4.1-lp152.2.3.1 |
| `tpm2.0-tools` | openSUSE:Leap 15.3 | All versions | 4.3.0-4.3.1 |

Products: Fedoraproject Fedora, Redhat Enterprise Linux, Tpm2-Tools Project Tpm2-Tools.

## How do I fix CVE-2021-3565?

Upgrade to a fixed version.

## Is CVE-2021-3565 being exploited?

There is no known exploitation of CVE-2021-3565 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3565 and fix it if it is affected.

What it is: CVE-2021-3565 is a medium-severity vulnerability in Fedoraproject Fedora, published on 4 Jun 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-2021-3565 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2021-3565/ (Markdown: https://insights.sbomify.com/CVE-2021-3565/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3565
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3565
- OSV: https://osv.dev/vulnerability/CVE-2021-3565

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3565/
Summaries are generated and may contain mistakes; the official description above is the record.