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Critical · 9.9 CVE-2026-66898 EUVD-2026-57545

Path traversal via unvalidated instance name in backup tarball restore enables root file write / RCE

Published Aug 12, 2026 · Updated Aug 13, 2026 · Assigned by canonical

Description

A path traversal vulnerability in LXD allows an attacker to manipulate file system paths during backup import and restore operations. When importing or restoring a backup archive, LXD fails to validate instance and storage volume names contained within the archive metadata. An attacker can exploit this flaw by supplying a crafted backup archive with malicious instance or volume names containing path traversal sequences, potentially allowing file access or overwriting outside the designated restore directory.

Affected products

VendorProductAffectedFixed
Canonical LXD 4.0.0 – < 4.0.12, 5.0.0 – < 5.0.4, 5.21.0 – < 5.21.2, 6.0 – < 6.1 4.0.12

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 lxd No fix yet —
Debian 12 lxd No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 20.04 LTS lxd No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 18.04 LTS lxd No fix yet —
Ubuntu Pro 16.04 LTS lxd No fix yet —
ReleasePackageFixed inAdvisory
openSUSE Leap 16.0 lxd 5.21.6-bp160.1.1 openSUSE-SU-2026:21788-1

Advisories 1

References