What’s Vulnerable › Vulnerabilities

CVE-2026-23954: Incus container image templating arbitrary host file read and write

• Severity: high (CVSS 8.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-22 · updated 2026-06-17
• Weakness: CWE-22

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.

Affected products

• lxc incus: through 6.0.5; from 6.1.0 before 6.21.0 — fixed in 6.21.0

How to fix

Upgrade to a fixed version: lxc incus 6.21.0. Check the vendor advisory for mitigations.

References

• 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/lxc/incus/security/advisories/GHSA-7f67-crqm-jgh7
• https://github.com/user-attachments/files/24473599/template_arbitrary_write.sh
• https://github.com/user-attachments/files/24473601/templates_arbitrary_write.patch

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