CVE-2026-8933

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Privilege Escalation in Snap-Confine via Ambient Capabilities

Publication date: 2026-07-21

Last updated on: 2026-07-22

Assigner: Canonical Ltd.

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.

CVSS Scores

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Meta Information

Published

2026-07-21

Last Modified

2026-07-22

Generated

2026-07-22

AI Q&A

2026-07-21

EPSS Evaluated

N/A

NVD

CVE-2026-8933

EUVD

EUVD-2026-46262

Affected Vendors & Products

Vendor	Product	Version / Range
canonical	snap_confine	*
canonical	snap-confine	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-250	The product performs an operation at a privilege level that is higher than the minimum level required, which creates new weaknesses or amplifies the consequences of other weaknesses.

Attack-Flow Graph

Executive Summary

This is a local privilege escalation vulnerability in snap-confine, a component used by Canonical's snapd to create secure environments for snap applications. It affects versions configured with set-capabilities instead of set-uid-root. A flaw in security sandbox initialization allows local attackers to bypass restrictions and execute arbitrary code, gaining full root access.

Detection Guidance

To detect this vulnerability, check if your system uses snap-confine with set-capabilities instead of set-uid-root. Run: 'dpkg -l snapd' to verify snapd installation. Then check snap-confine configuration with: 'getcap /usr/lib/snapd/snap-confine'. If it shows capabilities like CAP_SYS_ADMIN, the vulnerable configuration may exist.

Impact Analysis

If exploited, this vulnerability allows a local unprivileged user to escalate privileges to root on affected systems. This could lead to full system compromise, unauthorized data access, installation of malware, or disruption of services running on the machine.

Compliance Impact

This vulnerability allows local attackers to escalate privileges to root, which could lead to unauthorized access to sensitive data. For GDPR, this may result in data breaches requiring notification under Article 33. For HIPAA, it could compromise protected health information integrity or confidentiality, violating the Security Rule.

Mitigation Strategies

Update snapd to the latest version to ensure the vulnerable snap-confine is patched. Verify the update by checking the installed version of snapd and snap-confine. If using set-capabilities configurations, consider switching to standard set-uid-root installations for snap-confine as a temporary workaround.

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