Bubblewrap <0.12.0: Symlink Escape via /oldroot During Sandbox Setup
CVE-2026-87766 Published on September 9, 2026
Bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup
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.
Vulnerability Analysis
CVE-2026-87766 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
What is an insecure temporary file Vulnerability?
The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
CVE-2026-87766 has been classified to as an insecure temporary file vulnerability or weakness.
Products Associated with CVE-2026-87766
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