CVE-2026-23954
Publication date 23 January 2026
Last updated 23 January 2026
Ubuntu priority
Cvss 3 Severity Score
Description
Incus is a system container and virtual machine manager. Versions 6.21.0 and below allow a user with the ability to launch a container with a custom image (e.g a member of the ‘incus’ group) to use directory traversal or symbolic links in the templating functionality to achieve host arbitrary file read, and host arbitrary file write. This ultimately results in arbitrary command execution on the host. When using an image with a metadata.yaml containing templates, both the source and target paths are not checked for symbolic links or directory traversal. This can also be exploited in IncusOS. A fix is planned for versions 6.0.6 and 6.21.0, but they have not been released at the time of publication.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| incus | 25.10 questing |
Needs evaluation
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy | Not in release | |
| lxd | 25.10 questing | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score |
|
| Attack vector | Adjacent |
| Attack complexity | Low |
| Privileges required | Low |
| User interaction | None |
| Scope | Changed |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | None |
| Vector | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-23954
- https://github.com/lxc/incus/security/advisories/GHSA-7f67-crqm-jgh7
- https://github.com/lxc/incus/blob/HEAD/internal/server/instance/drivers/driver_lxc.go#L7215
- https://github.com/lxc/incus/blob/HEAD/internal/server/instance/drivers/driver_lxc.go#L7294
- https://github.com/user-attachments/files/24473599/template_arbitrary_write.sh
- https://github.com/user-attachments/files/24473601/templates_arbitrary_write.patch