Bug 2521023 (CVE-2026-62313)

Summary: CVE-2026-62313 github.com/lxc/incus: Incus: Project restriction bypass weakens container isolation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Incus, a system container and virtual machine manager. A user within a project configured to forbid non-isolated containers can bypass this restriction by omitting a specific security setting (`security.idmap.isolated`). This allows the creation of containers that share the host's user and group ID map, rather than receiving unique, non-overlapping ranges. Consequently, the isolation boundary between co-tenant containers and the host is weakened, potentially leading to unauthorized access or information disclosure within the shared environment.
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Bug Depends On: 2521985    
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Description OSIDB Bzimport 2026-08-21 15:13:22 UTC 
Incus is a system container and virtual machine manager. Prior to version 7.3.0, project-level enforcement of `restricted.containers.privilege=isolated` can be trivially bypassed, allowing a user to create a non-isolated (shared host idmap) container in a project that is configured to forbid them. The restriction only rejects an explicitly set `security.idmap.isolated=false` (or empty) and fails to enforce anything when the key is omitted entirely. Because an unset `security.idmap.isolated` defaults to `false` (non-isolation), a user simply leaves the key out and obtains exactly the container state the restriction is meant to forbid. This defeats the tenant-isolation guarantee the restriction exists to provide. Containers in the project share the host uid/gid map instead of receiving unique, non-overlapping ranges, weakening the isolation boundary between co-tenant containers and the host. Version 7.3.0 patches the issue.