---
title: "CVE-2026-87799\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-87799?format=md
keywords: index, follow
---

# CVE-2026-87799

Publication date 29 September 2026

Last updated 30 September 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**9.9 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2026-87799?format=md#impact-score)

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## Description

Improper link resolution in the migration receive path in Canonical LXD
versions 4.0 and later (fixed in 4.0.14, 5.0.10, 5.21.8 and 6.10) on Linux
allows an authenticated client that can create instances or custom storage
volumes in a project, or a malicious migration source server, to write
attacker-controlled files to arbitrary paths on the target host as root,
leading to full host compromise. The attacker does this with a crafted
rsync or btrfs send stream that plants a symlink in the transferred volume,
such as rootfs or root.img, and then writes through it.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| lxd | 26.04 LTS resolute | 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 |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.9 · Critical

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Changed |
  | Confidentiality impact | High |
  | Integrity impact | High |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.9 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-87799)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-87799)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-87799)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-87799)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-87799>
* <https://github.com/canonical/lxd/security/advisories/GHSA-fmc3-3cpq-6whr>