CVE-2026-8933: snap-confine Local Privilege Escalation via Capabilities Misconfiguration or Flaw in Execution Environment Setup

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-21 · updated 2026-07-22
Weakness: CWE-250

Description

A local privilege escalation vulnerability exists in snap-confine, a set-capabilities core component used internally by Canonical snapd to construct the secure execution environment for snap applications. This vulnerability uniquely affects versions of snap-confine configured with set-capabilities (rather than standard set-uid-root installations). Due to a flaw in how privilege boundaries or security sandboxes are initialized when the binary runs under limited ambient capabilities, a local, unprivileged attacker can exploit this behavior to bypass intended restrictions and execute arbitrary code. Successful exploitation allows the local user to elevate their privileges to full root authority.

Affected products

Canonical Ubuntu 22.04 LTS: all versions
Canonical Ubuntu 24.04 LTS: all versions
Canonical Ubuntu 26.04 LTS: all versions

References

https://ubuntu.com/security/CVE-2026-8933

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