Canonical LXD up to 4.0.13/5.0.9/5.21.7/6.9 Migration Receive Path link following

Summaryinfo

A vulnerability categorized as very critical has been discovered in Canonical LXD up to 4.0.13/5.0.9/5.21.7/6.9. This vulnerability affects unknown code of the component Migration Receive Path. Such manipulation leads to link following. This vulnerability is uniquely identified as CVE-2026-87799. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Canonical LXD up to 4.0.13/5.0.9/5.21.7/6.9 and classified as very critical. Affected by this issue is an unknown functionality of the component Migration Receive Path. The manipulation with an unknown input leads to a link following vulnerability. Using CWE to declare the problem leads to CWE-59. The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-87799 since 09/09/2026. The exploitation is known to be easy. The attack may be launched remotely. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/28/2026).

Upgrading to version 4.0.14, 5.0.10, 5.21.8 or 6.10 eliminates this vulnerability.

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Productinfo

Vendor

• Canonical

Name

• LXD

Version

• 4.0.0
• 4.0.1
• 4.0.2
• 4.0.3
• 4.0.4
• 4.0.5
• 4.0.6
• 4.0.7
• 4.0.8
• 4.0.9
• 4.0.10
• 4.0.11
• 4.0.12
• 4.0.13
• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.0.7
• 5.0.8
• 5.0.9
• 5.21.0
• 5.21.1
• 5.21.2
• 5.21.3
• 5.21.4
• 5.21.5
• 5.21.6
• 5.21.7
• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8
• 6.9

License

• open-source

Website

• Product: https://github.com/canonical/lxd/

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