CVE-2026-63125: CWE-59: Improper Link Resolution Before File Access ('Link Following') in lxc incus
Description
Incus is a system container and virtual machine manager. Prior to version 7.3.0, an unprivileged, project-confined Incus user (a non-admin TLS/RBAC identity with `can_create_images` and `can_create_instances`) can execute arbitrary code as root on the host. A crafted image ships `backup.yaml` as a symlink to a host file. When the root daemon writes the instance's backup file, it follows the symlink. Version 7.3.0 patches the issue.
CVSS v3.1
Score 9.9critical
Affected software
lxc
incus
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Incus versions before 7.3.0 contain a CWE-59 (Improper Link Resolution Before File Access) vulnerability where an unprivileged user with 'can_create_images' and 'can_create_instances' permissions can supply a crafted image containing a backup.yaml symlink pointing to a host file. When the root daemon writes the instance's backup file, it follows the symlink, allowing arbitrary code execution with root privileges on the host. This vulnerability is patched in version 7.3.0.
Potential Impact
An attacker with limited permissions inside Incus can escalate privileges to root on the host by exploiting the symlink vulnerability. This leads to complete host compromise, including confidentiality, integrity, and availability impacts as reflected by the CVSS score of 9.9.
Mitigation Recommendations
Upgrade Incus to version 7.3.0 or later, where this vulnerability is patched. No other official remediation or temporary fixes are indicated. Patch status is not explicitly confirmed in the vendor advisory, but the description states version 7.3.0 fixes the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-15T16:54:55.816Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a8869e8acd9273b494e4717
Added to database: 08/21/2026, 15:08:24 UTC
Last enriched: 08/21/2026, 15:22:51 UTC
Last updated: 10/05/2026, 18:48:21 UTC
Views: 96
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