# CVE-2021-3571: Information disclosure in linuxptp

> A remote attacker can cause an information leak or crash in ptp4l by sending crafted messages when running as a transparent clock on little-endian systems.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Jul 2021
- **Updated:** 3 Aug 2024
- **Also known as:** ALSA-2021:4321, DEBIAN-CVE-2021-3571, GHSA-3v9q-m45q-4cr7, OESA-2021-1267, RHSA-2021:4321, RLSA-2021:4321

## What is CVE-2021-3571?

CVE-2021-3571 is a high-severity vulnerability in Fedoraproject Fedora, published on 9 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw was found in the ptp4l program of the linuxptp package. When ptp4l is operating on a little-endian architecture as a PTP transparent clock, a remote attacker could send a crafted one-step sync message to cause an information leak or crash. The highest threat from this vulnerability is to data confidentiality and system availability. This flaw affects linuxptp versions before 3.1.1 and before 2.0.1.

Weakness: CWE-125 (Out-of-bounds Read), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2021-3571?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `linuxptp` | AlmaLinux:8 | All versions | 3.1.1-1.el8 |
| `linuxptp` | Red Hat:enterprise_linux:8::appstream | All versions | 0:3.1.1-1.el8 |
| `linuxptp-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 0:3.1.1-1.el8 |
| `linuxptp-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 0:3.1.1-1.el8 |
| `linuxptp` | Rocky Linux:8 | All versions | 0:3.1.1-1.el8 |

Products: Fedoraproject Fedora, Linuxptp Project Linuxptp, Redhat Enterprise Linux.

## How do I fix CVE-2021-3571?

Upgrade to a fixed version.

## Is CVE-2021-3571 being exploited?

There is no known exploitation of CVE-2021-3571 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-2021-3571 and fix it if it is affected.

What it is: CVE-2021-3571 is a high-severity vulnerability in Fedoraproject Fedora, published on 9 Jul 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-3571 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-2021-3571/ (Markdown: https://insights.sbomify.com/CVE-2021-3571/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3571
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3571
- OSV: https://osv.dev/vulnerability/CVE-2021-3571

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3571/
Summaries are generated and may contain mistakes; the official description above is the record.