GHSA-VHX5-8PFJ-7WRV
Vulnerability from github – Published: 2026-09-12 21:31 – Updated: 2026-09-12 21:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-90616"
],
"database_specific": {
"cwe_ids": [
"CWE-61"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-12T20:16:30Z",
"severity": "HIGH"
},
"details": "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.",
"id": "GHSA-vhx5-8pfj-7wrv",
"modified": "2026-09-12T21:31:12Z",
"published": "2026-09-12T21:31:12Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-8688-9x26-hhxj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90616"
},
{
"type": "WEB",
"url": "https://www.openwall.com/lists/oss-security/2026/08/11/9"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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