snapd snap-confine Sandbox Confinement Bypass via Omission of setuid Restriction in Seccomp Templates

Summary

A sandbox confinement bypass vulnerability exists in Canonical snapd within its internal execution environment compiler (snap-confine). The default seccomp security templates generated by the engine to restrict system calls do not filter or reject process operations capable of creating or manipulating file execution flags with set-user-ID attributes. Consequently, an application running within a strictly confined snap environment can successfully compile or drop binaries and apply setuid properties to them. If a compromised or malicious process inside the snap sandbox executes these generated setuid binaries, it can potentially circumvent architectural sandboxing assumptions, drop intended restriction policies, or execute privileged actions inside the container namespace that should otherwise be strictly blocked. The vulnerability has been resolved by hardening the seccomp template engine to block the execution and creation of setuid executables by sandboxed snap processes.

Timeline

1. Jul 21, 2026, 2:02 PM UTCCVE published
2. Jul 22, 2026, 6:15 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Jul 22, 2026, 6:28 PM UTCRecord last updated

Affected versions

• snapd

  fixed in 2.76.1

• snapd

  Version range not reported

• snapd

  Version range not reported

• snapd

  Version range not reported

• snapd

  Version range not reported

• snapd

  Version range not reported

• snapd

  Version range not reported

References 1