---
title: "CVE-2026-33897: Incus vulnerable to arbitrary file read and write through pongo templates"
url: https://erroneo.us/security/cve/CVE-2026-33897/
description: "CVE-2026-33897 (github.com/lxc/incus/v6 (Go)): Incus is a system container and virtual machine manager. Prior to version 6.23.0, instance template files can…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-26
date_modified: 2026-03-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-33897"
kev: false
cvss: 10
epss: 0.0053
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-33897: Incus vulnerable to arbitrary file read and write through pongo templates

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5% , percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes github.com/lxc/incus/v6 (Go) < 6.23.0, fixed in 6.23.0 ; github.com/lxc/incus (Go) <= 0.7.0, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Go `github.com/lxc/incus/v6` < 6.23.0 → fixed: 6.23.0
- Go `github.com/lxc/incus` <= 0.7.0 → fixed: none listed

## Affected products (CVE record)

- lxc incus: < 6.23.0

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.9 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.53% probability of exploitation activity in the next 30 days; percentile 44.

## Sources

- [GitHub Advisory GHSA-83xr-5xxr-mh92](https://github.com/advisories/GHSA-83xr-5xxr-mh92)
- [CVE.org record CVE-2026-33897](https://www.cve.org/CVERecord?id=CVE-2026-33897)
- [NVD entry CVE-2026-33897](https://nvd.nist.gov/vuln/detail/CVE-2026-33897)
- [github.com](https://github.com/lxc/incus/security/advisories/GHSA-83xr-5xxr-mh92)
- [github.com](https://github.com/lxc/incus/commit/487edf5984fad89b0f762c03a7e211fdd38396fb)

---
Source page: https://erroneo.us/security/cve/CVE-2026-33897/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt