# CVE-2021-28375: Missing authorization in n/a

> Local attackers can bypass authorization checks in the Linux kernel fastrpc driver to send unauthorized RPC messages, potentially leading to privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 15 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** A-183188047, ASB-A-183188047, AZL-6535, DEBIAN-CVE-2021-28375, GHSA-g79j-26m4-4gwc, UBUNTU-CVE-2021-28375

## What is CVE-2021-28375?

CVE-2021-28375 is a high-severity missing authorization vulnerability in Fedoraproject Fedora, published on 15 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in the Linux kernel through 5.11.6. fastrpc_internal_invoke in drivers/misc/fastrpc.c does not prevent user applications from sending kernel RPC messages, aka CID-20c40794eb85. This is a related issue to CVE-2019-2308.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2021-28375?

It affects 4 products.


Products: Fedoraproject Fedora, Linux kernel, Netapp Cloud Backup, Netapp Solidfire Baseboard Management Controller Firmware.

## How do I fix CVE-2021-28375?

Apply the vendor's patch.

## Is CVE-2021-28375 being exploited?

There is no known exploitation of CVE-2021-28375 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-2021-28375 and fix it if it is affected.

What it is: CVE-2021-28375 is a high-severity missing authorization vulnerability in Fedoraproject Fedora, published on 15 Mar 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-2021-28375 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-2021-28375/ (Markdown: https://insights.sbomify.com/CVE-2021-28375/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28375
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28375
- OSV: https://osv.dev/vulnerability/CVE-2021-28375

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28375/
Summaries are generated and may contain mistakes; the official description above is the record.