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Fencer Intel
critical 9.9

CVE-2026-63343 json

Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root

published 3mo ago modified 27d ago also EUVD-2026-63989 , GHSA-fmjx-5j3g-997p

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository lxc/incus. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.9
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 41%
public exploits
0
none known

Summary

Incus is a system container and virtual machine manager. Prior to version 7.3.0, a malicious image containing a `metadata.yaml` symlink pointing to an arbitrary host path allows an authenticated Incus user to read or overwrite any file on the host as root via the instance metadata API. The `exec-output` and `templates/` paths were patched in a prior release using `Lstat` rejection and `os.OpenRoot` confinement; `metadata.yaml` was not included in either patch and remains exploitable. Version 7.3.0 patches the issue.

Patch / fix

  • linuxcontainers incus 7.3.0
  • incus Debian 13 6.0.4-2+deb13u9
  • incus Debian 14 7.0.1-2

debian advisories DEBIAN-CVE-2026-63343

  • incus openSUSE Tumbleweed 7.4-1.1

opensuse advisories openSUSE-SU-2026:11651-1

Is CVE-2026-63343 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-63343 updated cvss 9.9

incus: Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • lxc incus

Classification

Weakness
  • CWE-73 External Control of File Name or Path

References

Sources

Fencer Intel 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.

The maintainers of lxc/incus published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.