---
cve: "CVE-2021-3492"
severity: "HIGH"
cvss: 8.8
epss: "1.5%"
vendor: "Ubuntu"
kev: false
exploited: false
published: "2021-04-17 05:15:13"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-19T02:39:20+02:00"
---

# CVE-2021-3492

> 8.8 HIGH · 🧪 PoC

## Beschreibung

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

## CVSS-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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 | Verändert | bad |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Referenzen

- <https://www.openwall.com/lists/oss-security/2021/04/16/2>
- <https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6>
- <https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333>
- <https://ubuntu.com/security/notices/USN-4917-1>
- <https://www.zerodayinitiative.com/advisories/ZDI-21-422/>
- <http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-3492) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_