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GHSA-MXG2-V7P6-PG5G

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

scsi: xen: scsiback: Free the command tag on the TMR submit-failure path

scsiback_device_action() obtains a command tag in scsiback_get_pend_req() and submits a task-management request with target_submit_tmr(). When target_submit_tmr() fails it returns < 0 and scsiback jumps to the err: label, which sends a response but frees nothing, leaking the tag.

Impact: a pvSCSI guest can leak the command tags of a LUN's session, stopping the LUN, by issuing VSCSIIF_ACT_SCSI_ABORT or RESET requests whenever target_submit_tmr() fails.

transport_generic_free_cmd() cannot be used here. By the time target_submit_tmr() returns an error it has already run __target_init_cmd() (so se_cmd->cmd_kref is one, not zero), and on its target_get_sess_cmd() error path it has freed se_cmd->se_tmr_req via core_tmr_release_req() while leaving SCF_SCSI_TMR_CDB set and the pointer dangling. Letting the command release run target_free_cmd_mem() would then double-free se_tmr_req.

Use the same helper, which returns just the tag, on this path too.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72086"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:22Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: xen: scsiback: Free the command tag on the TMR submit-failure path\n\nscsiback_device_action() obtains a command tag in\nscsiback_get_pend_req() and submits a task-management request with\ntarget_submit_tmr(). When target_submit_tmr() fails it returns \u003c 0 and\nscsiback jumps to the err: label, which sends a response but frees\nnothing, leaking the tag.\n\nImpact: a pvSCSI guest can leak the command tags of a LUN\u0027s session,\nstopping the LUN, by issuing VSCSIIF_ACT_SCSI_ABORT or RESET requests\nwhenever target_submit_tmr() fails.\n\ntransport_generic_free_cmd() cannot be used here. By the time\ntarget_submit_tmr() returns an error it has already run\n__target_init_cmd() (so se_cmd-\u003ecmd_kref is one, not zero), and on its\ntarget_get_sess_cmd() error path it has freed se_cmd-\u003ese_tmr_req via\ncore_tmr_release_req() while leaving SCF_SCSI_TMR_CDB set and the\npointer dangling. Letting the command release run target_free_cmd_mem()\nwould then double-free se_tmr_req.\n\nUse the same helper, which returns just the tag, on this path too.",
  "id": "GHSA-mxg2-v7p6-pg5g",
  "modified": "2026-08-15T06:32:11Z",
  "published": "2026-08-15T06:32:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72086"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1357fb32d42ad8da193e6da285f09e6452feabda"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/18d4f86816592586b38513543b5e1f9553bc271f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/255fb7b0cdc947b1c01929c7f133281342a3a6b5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4567ce79fe2f84c3dcc3a91b22a377cf482d33ad"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66aefc277ebb796ec285d550305535dc3fc0179f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6c01f0439098f00a64b246dc27479602201382f7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbc1bdede66d0f2cde83b75d6524ce1a815bb69f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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