[CRITICAL] CVE-2026-34177 — CVSS 9.1 (April 9, 2026)

A CRITICAL-severity vulnerability identified as CVE-2026-34177 has been published on April 9, 2026 with a CVSS base score of 9.1. This security advisory provides a detailed breakdown of the vulnerability, its potential impact, weakness classification, and actionable steps to protect your systems.

Vulnerability Details

CVE ID: CVE-2026-34177
Severity: CRITICAL
CVSS Score: 9.1
Published: April 9, 2026
Weakness (CWE): CWE-184

Technical Description

Canonical LXD versions 4.12 through 6.7 contain an incomplete denylist in isVMLowLevelOptionForbidden (lxd/project/limits/permissions.go), which omits raw.apparmor and raw.qemu.conf from the set of keys blocked under the restricted.virtual-machines.lowlevel=block project restriction. A remote attacker with can_edit permission on a VM instance in a restricted project can inject an AppArmor rule and a QEMU chardev configuration that bridges the LXD Unix socket into the guest VM, enabling privilege escalation to LXD cluster administrator and subsequently to host root.

Potential Impact

If exploited, this critical-severity vulnerability could allow an attacker to compromise sensitive data confidentiality, tamper with system integrity, cause a denial of service. Organizations running affected software should treat this as a priority remediation item.

Recommended Action

No official patch is available yet. Until one is released:

1. Monitor the official NVD page and vendor channels for patch announcements.
2. Restrict access to the affected system or service where possible.
3. Apply network-level mitigations such as firewall rules or WAF policies.
4. Enable logging and alerting for anomalous activity related to this vulnerability.
5. Review your incident response plan in case of active exploitation.

View full details on NVD →

References

• Reference 1
• Reference 2
• Reference 3

Related Security Advisories

• [CRITICAL] CVE-2026-34178 — CVSS 9.1 (April 9, 2026) — CRITICAL / CVSS 9.1
• [CRITICAL] CVE-2025-15379 — CVSS 10.0 (March 30, 2026) — CRITICAL / CVSS 10.0
• [CRITICAL] CVE-2026-3587 — CVSS 10.0 (March 23, 2026) — CRITICAL / CVSS 10.0