Symlink Following Affecting flatpak package, versions <1.16.6-1~deb13u3


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.18% (7th percentile)

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  • Snyk IDSNYK-ECHOLATEST-FLATPAK-19706676
  • published13 Sept 2026
  • disclosed12 Sept 2026

Introduced: 12 Sep 2026

CVE-2026-90616  (opens in a new tab)
CWE-61  (opens in a new tab)

How to fix?

Upgrade Echo:latest flatpak to version 1.16.6-1~deb13u3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream flatpak package and not the flatpak package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

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 Base Scores

version 3.1