Quick answers
- Is CVE-2026-86334 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-86334 being exploited in the wild.
- How severe is CVE-2026-86334?
- Medium severity, with a CVSS score of 4.2, published 28 September 2026.
- Which products and versions are affected?
- Canonical LXD 4.0.2 to before 4.0.14, 5.0.10, 5.21.8, and 6.10.
- Is there a fix for CVE-2026-86334?
- A patch was published on 2026-09-02: Fix merged in PR #18940 to main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-86334 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-86334?
- Check whether you run Canonical LXD at an affected version. 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 LXD's CLI image export and copy operations, where the Content-Disposition header filename parameter from server responses is not properly sanitized. An attacker controlling a malicious image server or performing a machine-in-the-middle attack can supply crafted filenames containing path traversal sequences (e.g., "../") to write files outside the intended directory during unified image operations targeting a local directory. The attack requires the client to initiate an image operation against the attacker's server.
Affected products
- Canonical LXD 4.0.2 to before 4.0.14, 5.0.10, 5.21.8, and 6.10
Timeline
- 2026-09-28: disclosed: CVE-2026-86334 published
- 2026-09-02: patched: Fix merged in PR #18940 to main branch
- 2026-09-11: patched: Fix backported to stable-5.21 branch in PR #18974