# CVE-2021-3569: Memory corruption in libtpms

> A stack corruption bug in libtpms during RSA decryption causes a SIGBUS and terminates swtpm, leading to denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-3569, GHSA-ppc8-jm88-74j3

## What is CVE-2021-3569?

CVE-2021-3569 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 3 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A stack corruption bug was found in libtpms in versions before 0.7.2 and before 0.8.0 while decrypting data using RSA. This flaw could result in a SIGBUS (bad memory access) and termination of swtpm. The highest threat from this vulnerability is to system availability.

Weakness: CWE-787 (Out-of-bounds Write), CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2021-3569?

It affects 2 products.


Products: Libtpms Project Libtpms, Redhat Enterprise Linux.

## How do I fix CVE-2021-3569?

Upgrade to a fixed version.

## Is CVE-2021-3569 being exploited?

There is no known exploitation of CVE-2021-3569 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2025-49133](https://insights.sbomify.com/CVE-2025-49133/): Libtpms contains a possible out-of-bound access and abort due to HMAC signing issue (medium 5.9)
- [CVE-2026-21444](https://insights.sbomify.com/CVE-2026-21444/): libtpms returns wrong initialization vector when certain symmetric ciphers are used (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3569 and fix it if it is affected.

What it is: CVE-2021-3569 is a medium-severity memory corruption vulnerability in Redhat Enterprise Linux, published on 3 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3569 in the wild and no public exploit code.

Affected product: Redhat Enterprise 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-2021-3569/ (Markdown: https://insights.sbomify.com/CVE-2021-3569/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3569
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3569
- OSV: https://osv.dev/vulnerability/CVE-2021-3569

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3569/
Summaries are generated and may contain mistakes; the official description above is the record.