Vulnerability Intelligence Report
Arbitrary file write on LXD host via symlink in migration stream
CVE-2026-87799
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.
No Active Exploit Signals
CVSS Base Score
9.9
CRITICAL
Exploitability:3.2
Impact Score:6.1
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
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Weaknesses (CWE)
CWE-59 ↗CWE-59 Improper link resolution before file access ('link following')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Canonical | LXD | 4.0.0 < 4.0.14 (affected), 5.0.0 < 5.0.10 (affected), 5.21.0 < 5.21.8 (affected), 6.0 < 6.10 (affected) |
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Canonical Ltd. · Vendor · UK |
| Reserved | 2026-09-09T10:00:46 |
| Published | 2026-09-28T13:22:29 |
| Patch Date | 2026-09-25 |
| Last Updated | 2026-09-29T03:55:19 |
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