Incus has Nil Dereferences on Restore via Malformed YAML

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-41684: 0.41% estimated exploitation activity in the next 30 days; percentile 35.14 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Details It was found that backup.GetInfo() trusts the inline backup/index.yaml config when present and only falls back to parsing the legacy backup/container/backup.yaml file if result.Config == nil. As a result, an archive can carry a valid inline config that passes the initial import preflight while also carrying a malformed legacy backup/container/backup.yaml file that is reparsed later from the restored file system. ParseConfigYamlFile() accepts YAML documents with no container section, and multiple downstream consumers then dereference .Container without checking for nil. Confirmed examples in the instance restore and import flow include backup.UpdateInstanceConfig() and internalImportFromBackup(). An authenticated user with permission to import instance backups may be able to crash the Incus daemon with a crafted backup archive whose inline backup/index.yaml is valid but whose extracted legacy backup.yaml omits container. The crash occurs in the restore path after…

Published by the source

4 May 2026, 19:45 UTC

Last modified by the source

8 May 2026, 21:47 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-x5r6-jr56-89pv

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# Patch Next advisory brief: CVE-2026-41684

Advisory: Incus has Nil Dereferences on Restore via Malformed YAML
IDs: CVE-2026-41684, GHSA-x5r6-jr56-89pv
Record: https://patchnext.com/advisories/cve-2026-41684 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/lxc/incus/v6/cmd/incusd: affected <= 6.23.0

## Suggested inspection (read-only)
- Go github.com/lxc/incus/v6/cmd/incusd: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/lxc/incus/v6/cmd/incusd.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-x5r6-jr56-89pv (GitHub-reviewed advisory GHSA-x5r6-jr56-89pv lists affected ranges: Go github.com/lxc/incus/v6/cmd/incusd >=0 <=6.23.0)

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