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CVE-2026-48756— Incus: CreateCustomVolumeFromBackup nil-pointer dereference on volume_snapshots[*].expires_at (sibling-field variant of GHSA-r7w7)

Quick assessment

Affected
lxc incus
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Incus 是一个系统容器和虚拟机管理器。在 7.1.0 版本之前， 文件中的 函数存在一个未加防护的 解引用操作，该操作作用于导入的自定义卷备份中每个卷快照条目的 字段。任何拥有项目 权限的已认证用户，都可以通过上传一个缺失 字段的备份压缩包，导致 守护进程崩溃。 这是 GHSA-r7w7-mmxr-47r9（CVE-2026-40197）漏洞的兄弟字段变体。提交 在循环体顶部添加了 检查，但并未对下方 19 行处的相邻 解引用操作进行防护。在同一文件中， 的其他所有使用者均已通过空值检查来保护解引用操作——这种

CVSS 2.1 · Low EPSS 0.23% · P14

Affected Version Matrix 1

VendorProduct Version RangeStatus
lxc incus < 7.1.0 affected
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I. Basic Information for CVE-2026-48756

Vulnerability Information
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Vulnerability Title
Incus: CreateCustomVolumeFromBackup nil-pointer dereference on volume_snapshots[*].expires_at (sibling-field variant of GHSA-r7w7)
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
空指针解引用
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
lxc incus < 7.1.0 -

II. Public POCs for CVE-2026-48756

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III. Intelligence Information for CVE-2026-48756

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Vendor Advisories for CVE-2026-48756 (1)

Same Patch Batch · lxc · 2026-08-21 · 18 CVEs total

CVE-2026-62941 9.9 CRITICAL Incus: Cross-project instance copy bypasses target project restrictions via TOCTOU in conf
CVE-2026-63343 9.9 CRITICAL Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as
CVE-2026-63125 9.9 CRITICAL Incus vulnerable to root RCE via image backup.yaml symlink
CVE-2026-48769 9.9 CRITICAL Incus has an arbitrary file write on its client due to trusted image hash
CVE-2026-48755 9.9 CRITICAL Incus has an argument injection in backup compression algorithm leading to AFW and ACE
CVE-2026-62867 9.9 CRITICAL Incus has an argument injection in storage volume block.create_options that leads to arbit
CVE-2026-62940 9.9 CRITICAL Incus has a project restriction bypass via instance migration config override
CVE-2026-48752 9.9 CRITICAL Incus has arbitrary file read+write on host via templates/ symlink in malicious image
CVE-2026-48751 9.9 CRITICAL Incus has a restricted project bypass leading to arbitrary command execution
CVE-2026-48753 9.9 CRITICAL Incus has an arbitrary file write via path traversal in S3 multipart upload
CVE-2026-48749 9.9 CRITICAL Incus has an arbitrary file read+write on host via rootfs/ symlink in malicious image
CVE-2026-48750 9.9 CRITICAL Incus has an arbitrary file write on host via `exec-output` symlink in crafted image
CVE-2026-55621 7.7 HIGH Incus has a project restriction bypass for custom volume copy across projects
CVE-2026-55622 7.7 HIGH Incus has a project restriction bypass in instance copy across projects
CVE-2026-47753 4.4 MEDIUM Incus has a Nil-Pointer Dereference Panic via Instance Backup Import (volume omitted)
CVE-2026-62313 4.3 MEDIUM Incus: Project restriction `restricted.containers.privilege=isolated` bypassable by omitti
CVE-2026-48754 2.1 LOW Incus: Nil-pointer dereference in createDependentVolumesFromBackup on disk.{Volume,VolumeS

IV. Related Vulnerabilities

Same product: incus
Same vendor: lxc
Same weakness: CWE-476

V. Comments for CVE-2026-48756

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