Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-09-09T00:00:00 bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H CWE-59

A flaw was found in bubblewrap. During sandbox setup, creating files or directories under the new root can follow a parent symlink onto the host via /oldroot, writing attacker-chosen paths outside the sandbox as the launching user. This happens before the sandboxed process starts. This issue is GHSA-pxhw-h44j-8pfx. It is fixed in bubblewrap 0.12.0.

This flaw in bubblewrap is rated as Important because it allows a local attacker to write files outside of a sandbox on the host system. This occurs during the initial setup phase, before any sandboxed process begins, by exploiting symlink traversal when processing untrusted application images, such as those used by Flatpak. While the created files are written with the privileges of the user launching bubblewrap, this can lead to unintended file creation on the host filesystem. Red Hat would like to thank geeknik for reporting this issue. Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds. Red Hat Enterprise Linux 10 Affected bubblewrap Red Hat Enterprise Linux 8 Affected bubblewrap Red Hat Enterprise Linux 9 Affected bubblewrap Red Hat Hardened Images Not affected bubblewrap https://www.cve.org/CVERecord?id=CVE-2026-87766 https://nvd.nist.gov/vuln/detail/CVE-2026-87766 https://bugs.debian.org/1145655 https://github.com/containers/bubblewrap/releases/tag/v0.12.0 https://github.com/containers/bubblewrap/security/advisories/GHSA-pxhw-h44j-8pfx https://www.openwall.com/lists/oss-security/2026/08/27/7