Arbitrary file read+write on host via templates/ symlink in malicious image

published 2026-08-12 2 mo ago modified 2026-10-23 16 d ago also EUVD-2026-57547

cvss: 8.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

A path traversal vulnerability in LXD allows an attacker to achieve arbitrary host file read or unconstrained file creation. When processing image metadata templates, LXD fails to properly sanitize or restrict template file paths from escaping the instance templates directory (specifically affecting virtual machine / QEMU driver execution paths). An attacker can exploit this flaw by providing a crafted image archive with malicious template directives containing path traversal sequences, causing LXD to access or write files outside the intended template directory on the host system.

Patch / fix

fixed in 1

Canonical LXD 4.0.12, 5.0.8

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 2 mo ago (2026-08-13)

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/canonical/lxd/security/advisories/GHSA-9hcm-hxh5-7xxh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Affected products

Canonical LXD

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

github.com /canonical/lxd/security/advisories/GHSA-9hcm-hxh5-7xxh
vdb-entry, vendor-advisory, exploit

Sources

CVE List CVE-2026-16033
NVD CVE-2026-16033

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary