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Fencer Vulns
critical 10.0

CVE-2026-33897 json

Incus vulnerable to arbitrary file read and write through pongo templates

published 2026-03-26 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-16466 , GHSA-83xr-5xxr-mh92 , GO-2026-4881

cvss
10.0
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 42%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/lxc/incus/v6 6.23.0
  • linuxcontainers incus 6.23.0
  • lxd Debian 13 5.0.2+git20231211.1364ae4-9+deb13u4
  • incus Debian 13 6.0.4-2+deb13u5
  • incus Debian 14 6.0.6-2

debian advisories DEBIAN-CVE-2026-33897

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • incus openSUSE Tumbleweed 6.23-1.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:10450-1

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-2026-33897 updated cvss 9.1

incus: pongo2: Incus: Arbitrary file read/write as root via pongo2 template chroot bypass

  • 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
yes
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
GitHub 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/lxc/incus/v6
<6.23.0
6.23.0
go github.com/lxc/incus
<=0.7.0
all versions
 no fix listed

Affected products

  • lxc incus

Classification

Weakness
  • CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine

References

Sources

Fencer Vulns 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.

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