Improper Neutralization of Special Elements Used in a Template Engine Affecting incus package, versions <6.0.4-2+deb13u5


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.48% (38th percentile)

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  • Snyk IDSNYK-ECHOLATEST-INCUS-18496045
  • published1 Aug 2026
  • disclosed26 Mar 2026

Introduced: 26 Mar 2026

CVE-2026-33897  (opens in a new tab)
CWE-1336  (opens in a new tab)

How to fix?

Upgrade Echo:latest incus to version 6.0.4-2+deb13u5 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream incus package and not the incus package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

Incus is a system container and virtual machine manager. Prior to version 6.23.0, instance template files can be used to cause arbitrary read or writes as root on the host server. Incus allows for pongo2 templates within instances which can be used at various times in the instance lifecycle to template files inside of the instance. This particular implementation of pongo2 within Incus allowed for file read/write but with the expectation that the pongo2 chroot feature would isolate all such access to the instance's filesystem. This was allowed such that a template could theoretically read a file and then generate a new version of said file. Unfortunately the chroot isolation mechanism is entirely skipped by pongo2 leading to easy access to the entire system's filesystem with root privileges. Version 6.23.0 patches the issue.