GHSA-3g2j-vm47-x4mj: Github.com/canonical/lxd LXD Vulnerable To A Local Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3g2j-vm47-x4mj",
  "modified" : "2025-11-18T18:40:12Z",
  "published" : "2025-11-13T23:01:44Z",
  "aliases" : [ ],
  "summary" : "LXD vulnerable to a local privilege escalation through custom storage volumes",
  "details" : "**Impact**\n\nThis affects any LXD user in an environment where an unprivileged user may have root access to a container with an attached custom storage volume that has the `security.shifted` property set to `true` as well as access to the host as an unprivileged user.\n\nThe most common case for this would be systems using `lxd-user` with the less privileged lxd group to provide unprivileged users with an isolated restricted access to LXD. Such users may be able to create a custom storage volume with the necessary property (depending on kernel and filesystem support) and can then write a setuid binary from within the container which can be executed as an unprivileged user on the host to gain root privileges.\n\n**Patches**\n\nPatches for this issue are available: \n\n- LXD 6 series: https://github.com/canonical/lxd/pull/16904\n- LXD 5.21 LTS series: https://github.com/canonical/lxd/pull/16922\n- LXD 5.0 LTS series: https://github.com/canonical/lxd/pull/16923\n- LXD 4.0 LTS series: https://github.com/canonical/lxd/pull/16924 \n\nThe first commit changes the permissions for any new storage pool, the later commit adds a patch that applies it on startup to all existing storage pools.\n\nThese fixes are also available in the associated candidate snap channels for each LTS series:\n\n- 5.21/candidate (5.21.4-8a3cf61)\n- 5.0/candidate (5.0.5-5c60378)\n- 4.0/candidate (4.0.10-35a8127)\n\nWe will be preparing intermediate releases to the associated stable snap channels shortly.\n\n**Workarounds**\n\nPermissions can be manually restricted until a patched version of LXD is deployed.\n\nThis is done with:\n\n```\nsudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0700 /var/snap/lxd/common/lxd/storage-pools/*/{custom*,virtual-machines*,images}\nsudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0711 /var/snap/lxd/common/lxd/storage-pools/*/{containers*,buckets*}\n```\n\nThose are the same permissions which will be applied by the patched LXD for both new and existing storage pools.\n\n**References**\n\nThis was reported to Incus publicly on Github here: \n\n- https://github.com/lxc/incus/security/advisories/GHSA-56mx-8g9f-5crf\n- https://github.com/lxc/incus/issues/2641",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/canonical/lxd"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.0-20251110144034-698854d0164f"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/canonical/lxd/security/advisories/GHSA-3g2j-vm47-x4mj"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/lxc/incus/security/advisories/GHSA-56mx-8g9f-5crf"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/lxc/incus/issues/2641"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/canonical/lxd/pull/16904"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/canonical/lxd/pull/16922"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/canonical/lxd/pull/16923"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/canonical/lxd/pull/16924"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/canonical/lxd"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-269" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-11-13T23:01:44Z",
    "nvd_published_at" : null
  }
}