CVE-2026-87799GHSA-fmc3-3cpq-6whr
Arbitrary file write on LXD host via symlink in migration stream
Canonical LXD
CVSS
9.9CriticalExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.41%Chance of exploitation activity in the next 30 days, higher than 33% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 4
- LXDaffected: 4.0.0 before 4.0.14CVE List
- LXDaffected: 5.0.0 before 5.0.10CVE List
- LXDaffected: 5.21.0 before 5.21.8CVE List
- LXDaffected: 6.0 before 6.10CVE List