CVE-2026-66898

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

State: Published
Severity: 9.9 Critical
Published: Aug 12, 2026
Updated: Aug 13, 2026
Reserved: Jul 28, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	9.9 Critical	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H	canonical

Weaknesses

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Affected Products

Product	Versions
LXDCanonical	4.0.0 to before 4.0.12Affected 5.0.0 to before 5.0.4Affected 5.21.0 to before 5.21.2Affected 6.0 to before 6.1Affected

References

https://github.com/canonical/lxd/security/advisories/GHSA-m857-c7gc-c984vdb-entryvendor-advisory

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