CVE-2026-87766

Summary

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

Weaknesses

• CWE-59: Improper Link Resolution Before File Access ('Link Following')

Workarounds

Do not create files on untrusted content with unpatched bwrap. Do not install untrusted Flatpaks. No upstream fix for older setuid builds.

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: total

CVE Program Container

Additional References

• http://www.openwall.com/lists/oss-security/2026/09/09/3

References

• 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

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