Vulnerability · Published Sep 28, 2026 · Assigned by canonical
CVE-2026-87799Arbitrary file write on LXD host via symlink in migration stream
Critical 9.9
In plain English
A critical-severity security flaw in LXD from Canonical. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | lxd | no fix listed | DEBIAN-CVE-2026-87799 |
| Debian:13 | lxd | no fix listed | DEBIAN-CVE-2026-87799 |
Affected products (as reported)
Weakness: CWE-59 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H