CVE-2026-87766
Bubblewrap: bubblewrap: symlink traversal via /oldroot allows writing files outside sandbox during setup
What happened?
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.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| bubblewrapRed Hat | unaffected: 0:0.10.0-5.el10_2 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.10.0-3.el10_0.4 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_10 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_4 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_4 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_6 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_6 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_8 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.0-3.el8_8 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.6.3-1.el9_8.1 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.1-7.el9_2.1 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.1-7.el9_4.1 to < * | See vendor advisory |
| bubblewrapRed Hat | unaffected: 0:0.4.1-8.el9_6.1 to < * | See vendor advisory |
| bubblewrapRed Hat | Default status: unaffected | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.
Sources and remediation references
- https://www.cve.org/CVERecord?id=CVE-2026-87766
- https://access.redhat.com/errata/RHSA-2026:85306
- https://access.redhat.com/errata/RHSA-2026:85308
- https://access.redhat.com/errata/RHSA-2026:85309
- https://access.redhat.com/errata/RHSA-2026:85312
- https://access.redhat.com/errata/RHSA-2026:85313
- https://access.redhat.com/errata/RHSA-2026:85317
- https://access.redhat.com/errata/RHSA-2026:85319
- https://access.redhat.com/errata/RHSA-2026:85322
- https://access.redhat.com/errata/RHSA-2026:85324
- https://access.redhat.com/errata/RHSA-2026:85325
- https://access.redhat.com/security/cve/CVE-2026-87766
- https://bugs.debian.org/1145655
- https://bugzilla.redhat.com/show_bug.cgi?id=2530542
- 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
- http://www.openwall.com/lists/oss-security/2026/09/09/3
- http://www.openwall.com/lists/oss-security/2026/09/22/23