# CVE-2026-48755: LXC Incus argument injection in backup compression algorithm

Source: https://junglewise.ai/threats/cve-2026-48755-lxc-incus-argument-injection-in-backup-compression-algorithm  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-21. Updated: 2026-06-26  
License: CC BY 4.0 with a link back

CVE-2026-48755 · Severity: critical · CVSS 9.9 · Published 2026-08-21

Incus, a container and virtual machine management tool, is vulnerable to a security flaw in its backup system. An attacker with the ability to request backups can inject malicious commands into the compression process. This allows them to write files anywhere on the host server, potentially leading to a full takeover of the system and all hosted virtual environments.

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

## Quick answers

**Is CVE-2026-48755 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48755 being exploited in the wild.

**How severe is CVE-2026-48755?** Critical severity, with a CVSS score of 9.9, published 21 August 2026.

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

**Is there a fix for CVE-2026-48755?** Yes. github.com/lxc/incus/v7 (Go): upgrade to 7.2.0 or later; github.com/lxc/incus/v7/cmd/incusd (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-2026-48755 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-48755?** Check whether you run github.com/lxc/incus (Go), github.com/lxc/incus/v6 (Go), github.com/lxc/incus/v7 (Go) or one of the others listed 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
  ```

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

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


## Technical details

An argument injection vulnerability exists in the `incusd` daemon of Incus due to improper validation of the `compression_algorithm` parameter during backup operations. While the software checks that the first token of the user-provided string is an allowed compression utility (e.g., zstd, gzip), it fails to reject additional arguments. These extra fields are appended to the command line executed by the host. An attacker can use flags like `-o` in `zstd` to write arbitrary content to sensitive host locations, such as `/etc/cron.d/`, to achieve remote code execution. This vulnerability is patched in version 7.2.0.

## Affected products

- LXC Incus < 7.2.0

## Identifiers

- CVE-2026-48755
- GHSA-v6mj-8pf4-hhw4
- GO-2026-5808

## Timeline

- 2026-06-25: advisory: Initial GHSA advisory published
- 2026-06-26: patched: Fix released in version 7.2.0

## 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)
- [Incus authorization bypass in custom volume copy](https://junglewise.ai/threats/cve-2026-55621-incus-authorization-bypass-in-custom-volume-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)
- [Incus nil-pointer dereference in createDependentVolumesFromBackup](https://junglewise.ai/threats/cve-2026-48754-incus-nil-pointer-dereference-in-createdependentvolumesfrombackup)