CVE-2026-72086 (GCVE-0-2026-72086)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:07
VLAI
Title
scsi: xen: scsiback: Free the command tag on the TMR submit-failure path
Summary
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 4567ce79fe2f84c3dcc3a91b22a377cf482d33ad (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 6c01f0439098f00a64b246dc27479602201382f7 (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 18d4f86816592586b38513543b5e1f9553bc271f (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < fbc1bdede66d0f2cde83b75d6524ce1a815bb69f (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 255fb7b0cdc947b1c01929c7f133281342a3a6b5 (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 1357fb32d42ad8da193e6da285f09e6452feabda (git)
Affected: 2dbcdf33dbf61f44b29adb52338282c3d7840d0e , < 66aefc277ebb796ec285d550305535dc3fc0179f (git)
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Linux Linux Affected: 4.6
Unaffected: 0 , < 4.6 (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "value": "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."
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    "dateReserved": "2026-08-09T03:40:39.905Z",
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            "value": "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."
          }
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        "id": "CVE-2026-72086",
        "lastModified": "2026-08-17T06:18:07.513",
        "metrics": {},
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      "current_release_date": "2026-08-17T21:41:24+00:00",
      "cve": "CVE-2026-72086",
      "id": "CVE-2026-72086",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: scsi: xen: scsiback: Free the command tag on the TMR submit-failure path",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72086.json",
      "version": "3"
    },
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      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:30:05Z",
      "cve": "CVE-2026-72086",
      "id": "CVE-2026-72086",
      "initial_release_date": "2026-08-28T01:01:02Z",
      "product_status:first_fixed": "23",
      "product_status:known_affected": "261",
      "product_status:known_not_affected": "101",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72086",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72086.json",
      "version": "4"
    }
  }
}



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