CVE-2026-72086: Linux kernel · scsi: xen: scsiback: Free the command tag on the TMR submit-failure path
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in fbc1bdede66d0f2cde83b75d6524ce1a815bb69f : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:19 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in fbc1bdede66d0f2cde83b75d6524ce1a815bb69f, 4567ce79fe2f84c3dcc3a91b22a377cf482d33ad, 1357fb32d42ad8da193e6da285f09e6452feabda +4
Exploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
Description
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.
References
- git.kernel.org/stable/c/4567ce79fe2f84c3dcc3a91b22a377cf482d33ad (opens in a new tab)
- git.kernel.org/stable/c/6c01f0439098f00a64b246dc27479602201382f7 (opens in a new tab)
- git.kernel.org/stable/c/18d4f86816592586b38513543b5e1f9553bc271f (opens in a new tab)
- git.kernel.org/stable/c/fbc1bdede66d0f2cde83b75d6524ce1a815bb69f (opens in a new tab)
- git.kernel.org/stable/c/255fb7b0cdc947b1c01929c7f133281342a3a6b5 (opens in a new tab)
- git.kernel.org/stable/c/1357fb32d42ad8da193e6da285f09e6452feabda (opens in a new tab)
- git.kernel.org/stable/c/66aefc277ebb796ec285d550305535dc3fc0179f (opens in a new tab)