# CVE-2026-63125: Incus vulnerable to root RCE via image backup.yaml symlink

> An unprivileged user can execute arbitrary code as root by crafting an image with a symlinked backup.yaml file, affecting Incus administrators.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-63125, GHSA-6rqx-22hc-qm36, UBUNTU-CVE-2026-63125

## What is CVE-2026-63125?

CVE-2026-63125 is a critical path traversal vulnerability in lxc incus, published on 21 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Incus is a system container and virtual machine manager. Prior to version 7.3.0, an unprivileged, project-confined Incus user (a non-admin TLS/RBAC identity with `can_create_images` and `can_create_instances`) can execute arbitrary code as root on the host. A crafted image ships `backup.yaml` as a symlink to a host file. When the root daemon writes the instance's backup file, it follows the symlink. Version 7.3.0 patches the issue.

Weakness: CWE-61 (UNIX Symbolic Link (Symlink) Following), CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2026-63125?


## How do I fix CVE-2026-63125?

Upgrade to a fixed version.

## Is CVE-2026-63125 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63125 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63125 and fix it if it is affected.

What it is: CVE-2026-63125 is a critical path traversal vulnerability in lxc incus, published on 21 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63125 exists.

Affected product: lxc incus. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63125/ (Markdown: https://insights.sbomify.com/CVE-2026-63125/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63125
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63125
- OSV: https://osv.dev/vulnerability/CVE-2026-63125

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63125/
Summaries are generated and may contain mistakes; the official description above is the record.