---
cve: "CVE-2019-15793"
severity: "MEDIUM"
cvss: 6.5
epss: "0.7%"
vendor: "Ubuntu"
kev: false
exploited: false
published: "2020-04-24 00:15:11"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T02:41:23+02:00"
---

# CVE-2019-15793

> 6.5 MEDIUM

## Beschreibung

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.

## CVSS-Vektor

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

| 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 | Keine | good |
| A Verfügbarkeit | Keine | good |

## Exploit-Evidenz

- [EDB-47693 — Ubuntu 19.10 - Refcount Underflow and Type Confusion in shiftfs](https://www.exploit-db.com/exploits/47693) ✅

## Referenzen

- <https://usn.ubuntu.com/usn/usn-4183-1>
- <https://usn.ubuntu.com/usn/usn-4184-1>
- <https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=3644b9d5688da86f18e017c9c580b75cf52927bb>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2019-15793) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_