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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-48749: 0.73% estimated exploitation activity in the next 30 days; percentile 54.34 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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

Published by the source

26 Jun 2026, 18:31 UTC

Last modified by the source

26 Jun 2026, 18:31 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2q3f-q5pq-g8wv

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# Patch Next advisory brief: CVE-2026-48749

Advisory: Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image
IDs: CVE-2026-48749, GHSA-2q3f-q5pq-g8wv
Record: https://patchnext.com/advisories/cve-2026-48749 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/lxc/incus/v7/cmd/incusd 7.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/lxc/incus/v7/cmd/incusd: affected < 7.2.0; fixed in 7.2.0

## Suggested inspection (read-only)
- Go github.com/lxc/incus/v7/cmd/incusd: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/lxc/incus/v7/cmd/incusd.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2q3f-q5pq-g8wv (GitHub-reviewed advisory GHSA-2q3f-q5pq-g8wv lists affected ranges: Go github.com/lxc/incus/v7/cmd/incusd >=0 <7.2.0)

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