ubuntu-cve-2021-41133
Vulnerability from osv_ubuntu
Published
2021-10-08 14:15
Modified
2026-04-22 07:40
Summary
Details

Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into treating the Flatpak app as though it was an ordinary, non-sandboxed host-OS process. They can do this by manipulating the VFS using recent mount-related syscalls that are not blocked by Flatpak's denylist seccomp filter, in order to substitute a crafted /.flatpak-info or make that file disappear entirely. Flatpak apps that act as clients for AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can escalate the privileges that the corresponding services will believe the Flatpak app has. Note that protocols that operate entirely over the D-Bus session bus (user bus), system bus or accessibility bus are not affected by this. This is due to the use of a proxy process xdg-dbus-proxy, whose VFS cannot be manipulated by the Flatpak app, when interacting with these buses. Patches exist for versions 1.10.4 and 1.12.0, and as of time of publication, a patch for version 1.8.2 is being planned. There are no workarounds aside from upgrading to a patched version.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.0.9-0ubuntu0.4"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.0.9-0ubuntu0.4"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.0.9-0ubuntu0.4"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.0.9-0ubuntu0.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.0.9-0ubuntu0.4?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.0.9-0ubuntu0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8.7-5",
        "0.10.0-1",
        "0.10.0-2",
        "0.10.1-1",
        "0.10.2-1",
        "0.10.2.1-1",
        "0.10.2.1-2",
        "0.10.3-1",
        "0.11.1-0ubuntu1",
        "0.11.3-2",
        "0.11.3-3",
        "0.11.7-0ubuntu0.1",
        "1.0.1-0ubuntu0.1",
        "1.0.6-0ubuntu0.1",
        "1.0.7-0ubuntu0.18.04.1",
        "1.0.8-0ubuntu0.18.04.1",
        "1.0.9-0ubuntu0.1",
        "1.0.9-0ubuntu0.2",
        "1.0.9-0ubuntu0.3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "flatpak",
            "binary_version": "1.6.5-0ubuntu0.4"
          },
          {
            "binary_name": "flatpak-tests",
            "binary_version": "1.6.5-0ubuntu0.4"
          },
          {
            "binary_name": "gir1.2-flatpak-1.0",
            "binary_version": "1.6.5-0ubuntu0.4"
          },
          {
            "binary_name": "libflatpak0",
            "binary_version": "1.6.5-0ubuntu0.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "flatpak",
        "purl": "pkg:deb/ubuntu/flatpak@1.6.5-0ubuntu0.4?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.6.5-0ubuntu0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.4.3-1",
        "1.6.0-1",
        "1.6.1-1",
        "1.6.2-1",
        "1.6.3-1",
        "1.6.5-0ubuntu0.1",
        "1.6.5-0ubuntu0.2",
        "1.6.5-0ubuntu0.3"
      ]
    }
  ],
  "aliases": [],
  "details": "Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. In versions prior to 1.10.4 and 1.12.0, Flatpak apps with direct access to AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can trick portals and other host-OS services into treating the Flatpak app as though it was an ordinary, non-sandboxed host-OS process. They can do this by manipulating the VFS using recent mount-related syscalls that are not blocked by Flatpak\u0027s denylist seccomp filter, in order to substitute a crafted `/.flatpak-info` or make that file disappear entirely. Flatpak apps that act as clients for AF_UNIX sockets such as those used by Wayland, Pipewire or pipewire-pulse can escalate the privileges that the corresponding services will believe the Flatpak app has. Note that protocols that operate entirely over the D-Bus session bus (user bus), system bus or accessibility bus are not affected by this. This is due to the use of a proxy process `xdg-dbus-proxy`, whose VFS cannot be manipulated by the Flatpak app, when interacting with these buses. Patches exist for versions 1.10.4 and 1.12.0, and as of time of publication, a patch for version 1.8.2 is being planned. There are no workarounds aside from upgrading to a patched version.",
  "id": "UBUNTU-CVE-2021-41133",
  "modified": "2026-04-22T07:40:10Z",
  "published": "2021-10-08T14:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-41133"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-67h7-w3jq-vh4q"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5191-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-41133"
    }
  ],
  "related": [
    "USN-5191-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-41133"
  ]
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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