---
cve: "CVE-2021-47461"
severity: "HIGH"
cvss: 7.8
epss: "17%"
vendor: "Linux"
kev: false
exploited: false
published: "2024-05-22 07:15:11"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-12T06:58:37+02:00"
---

# CVE-2021-47461

> 7.8 HIGH

## Beschreibung

In the Linux kernel, the following vulnerability has been resolved:

userfaultfd: fix a race between writeprotect and exit_mmap()

A race is possible when a process exits, its VMAs are removed by
exit_mmap() and at the same time userfaultfd_writeprotect() is called.

The race was detected by KASAN on a development kernel, but it appears
to be possible on vanilla kernels as well.

Use mmget_not_zero() to prevent the race as done in other userfaultfd
operations.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Referenzen

- <https://git.kernel.org/stable/c/3cda4bfffd4f755645577aaa9e96a606657b4525>
- <https://git.kernel.org/stable/c/149958ecd0627a9f1e9c678c25c665400054cd6a>
- <https://git.kernel.org/stable/c/cb185d5f1ebf900f4ae3bf84cee212e6dd035aca>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-47461) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_