# CVE-2026-55621: Incus authorization bypass in custom volume copy

Source: https://junglewise.ai/threats/cve-2026-55621-incus-authorization-bypass-in-custom-volume-copy  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-21. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-55621 · Severity: high · CVSS 7.7 · Published 2026-08-21

Incus, a container and virtual machine management system, contains a flaw that allows authenticated users to copy storage volumes from projects they are not authorized to access. An attacker with access to one project can copy sensitive data stored in custom volumes belonging to restricted projects, leading to unauthorized information disclosure. The vulnerability requires network access and valid credentials but no user interaction.

Technologies: [github.com/lxc/incus (Go)](https://junglewise.ai/threats/technologies/github-com-lxc-incus), [github.com/lxc/incus/v6 (Go)](https://junglewise.ai/threats/technologies/github-com-lxc-incus-v6), [github.com/lxc/incus/v7 (Go)](https://junglewise.ai/threats/technologies/github-com-lxc-incus-v7). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-55621 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55621 being exploited in the wild.

**How severe is CVE-2026-55621?** High severity, with a CVSS score of 7.7, published 21 August 2026.

**Which products and versions are affected?** github.com/lxc/incus (Go) <= 0.7.0, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=0.7.0; github.com/lxc/incus/v6 (Go) <= 6.23.0, SEMVER:introduced=0, SEMVER:introduced=0,last_affected=6.23.0; github.com/lxc/incus/v7 (Go) < 7.2.0, SEMVER:introduced=0,fixed=7.2.0.

**Is there a fix for CVE-2026-55621?** Yes. github.com/lxc/incus/v7 (Go): upgrade to 7.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55621 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-55621?** Check whether you run github.com/lxc/incus (Go), github.com/lxc/incus/v6 (Go) or github.com/lxc/incus/v7 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/lxc/incus/v7 (Go): upgrade to 7.2.0 or later

  ```sh
  go get github.com/lxc/incus/v7@v7.2.0
  ```


## Technical details

The vulnerability exists in the storage volume creation handler, which authorizes creation in the target project but fails to validate that the caller has permission to view the source volume before invoking the custom-volume copy path. The attacker-controlled `req.Source.Project` field is passed directly to `CreateCustomVolumeFromCopy` without any authorization checks (e.g., `allowPermission` or `CanView` entitlements). The copy operation must occur on the same server initially, but once created, nothing prevents the attacker from moving the volume elsewhere. The attack is feasible against remotely accessible Incus instances where the attacker has a valid client certificate or credentials restricted to certain projects. Exploitation requires knowing or guessing the target project name and volume name.

## Affected products

- LXC Incus v7 < 7.2.0, v6 <= 6.23.0, <= 0.7.0

## Identifiers

- CVE-2026-55621
- GHSA-64f3-v33m-w89f
- GO-2026-6318

## Timeline

- 2026-06-25: disclosed
- 2026-06-25: patched: Patched in v7.2.0
- 2026-08-28: advisory

## References

- [https://api.github.com/users/antifob](https://api.github.com/users/antifob)
- [https://github.com/antifob](https://github.com/antifob)
- [https://api.github.com/users/antifob/gists%7B/gist_id%7D](https://api.github.com/users/antifob/gists%7B/gist_id%7D)
- [https://api.github.com/users/antifob/repos](https://api.github.com/users/antifob/repos)
- [https://avatars.githubusercontent.com/u/25389335?v=4](https://avatars.githubusercontent.com/u/25389335?v=4)
- [https://api.github.com/users/antifob/events%7B/privacy%7D](https://api.github.com/users/antifob/events%7B/privacy%7D)

## Related threats

- [Incus project restriction bypass in instance copy](https://junglewise.ai/threats/cve-2026-55622-incus-project-restriction-bypass-in-instance-copy)
- [LXC Incus arbitrary file write via image hash path traversal](https://junglewise.ai/threats/cve-2026-48769-lxc-incus-arbitrary-file-write-via-image-hash-path-traversal)
- [LXC Incus nil-pointer dereference in CreateCustomVolumeFromBackup](https://junglewise.ai/threats/cve-2026-48756-lxc-incus-nil-pointer-dereference-in-createcustomvolumefrombackup)
- [LXC Incus argument injection in backup compression algorithm](https://junglewise.ai/threats/cve-2026-48755-lxc-incus-argument-injection-in-backup-compression-algorithm)
- [Incus nil-pointer dereference in createDependentVolumesFromBackup](https://junglewise.ai/threats/cve-2026-48754-incus-nil-pointer-dereference-in-createdependentvolumesfrombackup)