CVE-2026-15226 PUBLISHED

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

Assigner: canonical
Reserved: 09.07.2026 Published: 21.07.2026 Updated: 21.07.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
CVSS Score: 8.4

Product Status

Package Collection https://github.com/canonical
Package Name snapd
Versions Default: unaffected
  • affected from 0 to 2.76.1 (excl.)
Vendor Canonical
Product Ubuntu 26.04 LTS
Versions Default: affected
  • Version 2.76+ubuntu26.04.3 is unaffected
Vendor Canonical
Product Ubuntu 24.04 LTS
Versions Default: affected
  • Version 2.76+ubuntu24.04.1 is unaffected
Vendor Canonical
Product Ubuntu 22.04 LTS
Versions Default: affected
  • Version 2.76+ubuntu22.04.1 is unaffected
Vendor Canonical
Product Ubuntu 20.04 LTS
Versions Default: affected
  • Version 2.67.1+20.04ubuntu1~esm2 is unaffected
Vendor Canonical
Product Ubuntu 18.04 LTS
Versions Default: affected
  • Version 2.61.4ubuntu0.18.04.1+esm3 is unaffected
Vendor Canonical
Product Ubuntu 16.04 LTS
Versions Default: affected
  • Version 2.61.4ubuntu0.16.04.1+esm3 is unaffected

Credits

  • Zygmunt Krynicki finder

References

Problem Types

  • CWE-250 Execution with unnecessary privileges CWE

Impacts

  • CAPEC-122 Privilege Abuse