CVE-2026-63300
Authenticated user can bypass LXD project restrictions by migrating instances.
Is CVE-2026-63300 being exploited?
Not confirmed. CVE-2026-63300 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.36% probability of exploitation in the next 30 days.
How severe is CVE-2026-63300?
CVE-2026-63300 is rated Critical with a CVSS score of 9.9. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63300?
Yes. A fix has been recorded for CVE-2026-63300. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63300 affect?
CVE-2026-63300 affects LXD (Canonical), lxd/instance_post.go. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63300?
Apply vendor patch when released; block instance migrations and restrict can_create_instances.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated user with can_create_instances can migrate disallowed/high-privilege containers into restricted projects, bypassing project restrictions and enabling privilege escalation.
Immediate action required
- affected>= 5.0.0 and < 5.0.8
- affected>= 5.21.0 and < 5.21.6
- affected>= 6.0 and < 6.10
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.