{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-80928",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-80928"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "smack: fix cred UAF in smack_file_send_sigiotask()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmack: fix cred UAF in smack_file_send_sigiotask()\n\nWhen inspecting the credentials of another task, objective credentials\n(->real_cred, accessed with __task_cred()) must always be used.\n\nAccessing ->cred on a non-current task is forbidden unless that task is\nbeing created or destroyed; a task is allowed to change its own ->cred\npointer with no synchronization, and changing ->cred should only affect the\ncurrent syscall.\n\nsmack_file_send_sigiotask() was accessing both sets of credentials: First\ntsk->cred, then __task_cred(tsk).\n\nFix it, always access the objective credentials here.\n\nI have tested that this bug can lead to a KASAN-reported UAF of struct cred\nin smack_file_send_sigiotask(), and that this fix prevents the race.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-80928"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a512366d84e134a9eefc2cc40eeb6e80e2ec162c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7c7fe043f3099d0d35002b248967f75e55345b93"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f9c7b1f2b9d8f4176d2632743f51400855978ace"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b5bcf3adfa27279da4401ab8f1e1a706601a92be"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ed64aa505875a3b4defd504ee8e59e1949246a62"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b791401bf389a1546a830d2b381ca60fe94c7870"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fedc88e38ce979a720cd2de042578cb5df3dc8de"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-14T12:06:03Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - Reachable only via local syscalls: fcntl(F_SETOWN)/O_ASYNC on a pipe or socket, then write or MSG_OOB so kill_fasync()/send_sigurg() call smack_file_send_sigiotask(). Same SIGIO path as CVE-2026-72183 (AV:L); a remote peer can raise SIGIO only on a socket the local attacker already owns.\nAC:L - The attacker controls both sides of the race: one thread loops faccessat() so access_override_creds() installs a non_rcu subjective cred that revert_creds()+put_cred() frees without RCU, while another thread writes the pipe or sends OOB to fire SIGIO. The fix author reproduced a KASAN cred UAF; the window is retryable.\nPR:L - pipe(), fcntl(F_SETOWN/F_SETFL), write(), and faccessat() need no capabilities. An unprivileged user namespace (unshare(CLONE_NEWUSER)) makes access() install the non_rcu override (non-root uid with caps, or real uid != fsuid). The UAF is kernel cred memory on the attacker\u2019s own task.\nUI:N - No victim action is required. The attacker arms fowner on their own file, overrides their own subjective creds via faccessat(), and triggers SIGIO themselves.\nS:U - This is in-kernel cred use-after-free leading to local privilege escalation within the kernel security authority. It is not a VM escape, IOMMU bypass, or userspace sandbox boundary crossing.\nC:H - This is a use-after-free of struct cred. After free, the cred slab can be sprayed so cred->security and the derived smack_known are attacker-controlled, enabling arbitrary kernel reads through smk_access() and smack_log(). Kernel UAF scores C:H.\nI:H - The same sprayed cred/task_smack/smack_known objects yield a fake-object primitive on the SIGIO path, exploitable for control-flow hijacking and arbitrary write as with other kernel cred UAFs. Kernel UAF scores I:H.\nA:H - The fix author confirmed a KASAN use-after-free of struct cred in smack_file_send_sigiotask(). Dereferencing the freed cred on the SIGIO path, including from kill_fasync() in interrupt context, causes a kernel oops or panic."
    }
  }
}