CVE-2026-34178 | Importing a crafted backup leads to project restriction bypass

Exp

In Canonical LXD before 6.8, the backup import path validates project restrictions against backup/index.yaml in the supplied tar archive but creates the instance from backup/container/backup.yaml, a separate file in the same archive that is never checked against project restrictions. An authenticated remote attacker with instance-creation permission in a restricted project can craft a backup archive where backup.yaml carries restricted settings such as security.privileged=true or raw.lxc directives, bypassing all project restriction enforcement and allowing full host compromise.

Published: 2026-04-09 Last update: 2026-04-22 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34178 is rated Exploit Available (57.1/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.05%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-34178

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-34178

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-11 0.05% 0.05% +0.00%
2 2026-04-23 0.05% 0.05% -0.00%
3 2026-04-15 — 0.05% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34178

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.3 6.0 [email protected]

Weakness enumeration for CVE-2026-34178

GitHub Security Advisory for CVE-2026-34178

GHSA-q96j-3fmm-7fv4 · Severity: critical · Ecosystem: go — LXD: Importing a crafted backup leads to project restriction bypass

OS Trackers for CVE-2026-34178

vendor priority summary link
debian not yet assigned CVE-2026-34178 not yet assigned priority: Debian including 2 source packages (incus, lxd), 5 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2026-34178
ubuntu medium CVE-2026-34178 medium priority: Ubuntu including 2 source packages (incus, lxd), 13 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): DNE 5, not-affected 3, needed 2, needs-triage 2, released 1. https://ubuntu.com/security/CVE-2026-34178

Affected software / configurations for CVE-2026-34178

Vendor Product Version Raw CPE
canonical lxd >= 4.12, <= 5.0.6 cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*
canonical lxd >= 5.21.0, <= 5.21.4 cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*
canonical lxd >= 6.0, <= 6.7 cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*

References for CVE-2026-34178

cvelogic Threat Intelligence