CVE intelligence and bounded remediation

CVE-2026-33945 — Incus is a system container and virtual machine manager

Critical CVSS 9.9

Incus is a system container and virtual machine manager. Incus instances have an option to provide credentials to systemd in the guest. For containers, this is handled through a shared directory. Prior to version 6.23.0, an attacker can set a configuration key named something like `systemd.credential.../../../../../../root/.bashrc` to cause Incus to write outside of the `credentials` directory associated with the container. This makes use of the fact that the Incus syntax for such credentials is `systemd.credential.XYZ` where `XYZ` can itself contain more periods. While it's not possible to read any data this way, it's possible to write to arbitrary files as root, enabling both privilege escalation and denial of service attacks. Version 6.23.0 fixes the issue.

Severity
Critical
CVSS
9.9 (3.1)
Published
2026-03-27
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • linuxcontainers / incus

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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