Quick answers
- Is CVE-2026-85526 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-85526 being exploited in the wild.
- How severe is CVE-2026-85526?
- Critical severity, with a CVSS score of 9.9, published 28 September 2026.
- Which products and versions are affected?
- Canonical LXD.
- Is there a fix for CVE-2026-85526?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-85526 attacked?
- It is attacked over the network, in a network appliance.
- Am I affected by CVE-2026-85526?
- Check whether you run Canonical LXD. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in the unpackVolume function of the Btrfs storage driver, which fails to properly validate the subvolumes[].path entries during the import of optimized Btrfs backups from backup/optimized_header.yaml. An authenticated attacker can supply a crafted path containing traversal sequences (e.g., /../) to escape the intended backup directory and read, write, or delete files anywhere on the host filesystem with root privileges. No elevated privileges beyond instance creation are required to trigger the attack.
Affected products
- Canonical LXD
Timeline
- 2026-09-28: disclosed