CVE-2026-48756 Incus: CreateCustomVolumeFromBackup nil-pointer dereference on volume_snapshots[*].expires_at (sibling-field variant of GHSA-r7w7)
An authenticated user can crash the Incus daemon by uploading a backup tarball with missing snapshot expiration fields, causing a null pointer dereference.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48756?
CVE-2026-48756 is a low-severity vulnerability in lxc incus, published on 21 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Incus is a system container and virtual machine manager. Prior to version 7.1.0, `(*backend).CreateCustomVolumeFromBackup` in `internal/server/storage/backend.go` contains an unguarded `*time.Time` dereference on the `ExpiresAt` field of every volume-snapshot entry in an imported custom-volume backup. An authenticated user with `can_create_storage_volumes` permission on any project can crash the `incusd` daemon by uploading a backup tarball whose `volume_snapshots[*].expires_at` field is absent. This is a sibling-field variant of GHSA-r7w7-mmxr-47r9 (CVE-2026-40197). Commit `985a1dedf9f3e7ba729c93b654905ed510de25c2` added `if s == nil` at the top of the loop body, but did not guard the adjacent `*snapshot.ExpiresAt` deref 19 lines later. Every other consumer of `Config.VolumeSnapshots[i].ExpiresAt` in this same file already gates the deref with a nil-check — the asymmetric guard is the bug. Version 7.1.0 contains an updated patch.
Weakness: CWE-476
Which versions are affected by CVE-2026-48756?
5 open source packages ship an affected version, including github.com/lxc/incus/v7/cmd/incusd, github.com/lxc/incus and github.com/lxc/incus/v6.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lxc/incus/v7/cmd/incusd Go | All versions | 7.1.0 |
github.com/lxc/incus/v7/cmd/incusd Go | All versions | 7.1.0 |
github.com/lxc/incus Go | All versions | None |
github.com/lxc/incus/v6 Go | All versions | None |
github.com/lxc/incus/v7 Go | All versions | 7.1.0 |
How do I fix CVE-2026-48756?
Upgrade github.com/lxc/incus/v7/cmd/incusd to 7.1.0 or later.
Is CVE-2026-48756 being exploited?
There is no known exploitation of CVE-2026-48756 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-48756, GHSA-xhqx-mgh3-3h7q, GO-2026-5810, UBUNTU-CVE-2026-48756.