---
cve: "CVE-2026-90616"
severity: "HIGH"
cvss: 7.4
epss: "0.2%"
vendor: "flatpak"
kev: false
exploited: false
published: "2026-09-12 20:16:30"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-24T21:02:14+02:00"
---

# CVE-2026-90616

> 7.4 HIGH · 🧪 PoC

## Beschreibung

In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- abc06c8bf434171e931426e76a9eb0bfe17cfabd (Commit)

## Referenzen

- <https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj>
- <https://www.openwall.com/lists/oss-security/2026/08/11/9>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-90616) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_