PatchSiren cyber security CVE debrief
CVE-2026-72086 Linux CVE debrief
The Linux kernel has a vulnerability in the scsi: xen: scsiback module. When a task-management request submission fails, the command tag is not freed, potentially leading to a leak of command tags for a LUN's session. This issue can be triggered by a pvSCSI guest issuing VSCSIIF_ACT_SCSI_ABORT or RESET requests. The vulnerability has been resolved by freeing the command tag on the TMR submit-failure path. Affected systems should be inventoried and patched, with compensating controls implemented to mitigate potential exploitation. Monitoring for exploitation attempts is also recommended.
- Vendor
- Linux
- Product
- Unknown
- CVSS
- Unknown
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-08-15
- Original CVE updated
- 2026-08-15
- Advisory published
- 2026-08-15
- Advisory updated
- 2026-08-15
Who should care
System administrators and security teams responsible for Linux kernel-based systems, particularly those using pvSCSI guests, should be aware of this vulnerability and take necessary actions to mitigate it. This includes inventorying affected systems, applying patches, and implementing compensating controls. Security teams should also monitor for potential exploitation attempts and review system logs for suspicious activity. Additionally, operators of affected platforms and vulnerability management teams should prioritize patching and review their security controls to ensure they are adequate to protect against this vulnerability. Those responsible for change management and incident response should also be aware of the potential impact of this vulnerability and have plans in place to respond quickly in case of an exploit. The vulnerability management process should be updated to include checks for this vulnerability, and asset owners should be notified of the potential risk. Security teams should also review their monitoring and detection capabilities to ensure they can detect potential exploitation attempts. The incident response plan should be updated to include procedures for responding to an exploit of this vulnerability. Those responsible for source tracking and vulnerability management should also review their processes to ensure they are adequate to detect and respond to this vulnerability. Compensating controls, such as additional monitoring or restrictions on access, may be necessary for systems that cannot be patched immediately. The vulnerability should be prioritized based on its potential impact and the likelihood of exploitation. Those responsible for Linux kernel-based systems should review their systems for potential exposure and take necessary actions to mitigate the vulnerability. The vulnerability should be addressed through a coordinated effort between system administrators, security teams, and vulnerability management teams. Those responsible for security awareness and training should also be notified of the vulnerability and its potential impact, so they can provide guidance to system administrators and users on how to mitigate it. The patch
Technical summary
The vulnerability is in the scsiback_device_action() function, which obtains a command tag and submits a task-management request. If the submission fails, the function jumps to the err: label, which sends a response but does not free the tag. This can lead to a leak of command tags for a LUN's session. The issue has been resolved by freeing the command tag on the TMR submit-failure path. System administrators and security teams should review the vulnerability and implement necessary mitigations.
Defensive priority
Medium
Recommended defensive actions
- Inventory affected systems and apply the patch
- Monitor for potential exploitation attempts
- Implement compensating controls to mitigate the vulnerability
- Review system logs for suspicious activity
- Verify patch deployment and system security
- Update incident response plans to include procedures for responding to an exploit
- Notify asset owners of the potential risk and necessary actions
Evidence notes
The vulnerability is caused by a failure to free the command tag when a task-management request submission fails. The issue is in the scsiback_device_action() function, which obtains a command tag and submits a task-management request. If the submission fails, the function jumps to the err: label, which sends a response but does not free the tag. This can lead to a leak of command tags for a LUN's session.
Sources and references
Verified primary and authoritative sources
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CVE-2026-72086 CVE Program record
Publisher, destination, and source semantics verified
URL: https://www.cve.org/CVERecord?id=CVE-2026-72086
CVE Program - Official CVE Program record with source-provided CVE metadata.
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CVE-2026-72086 NVD vulnerability detail
Publisher, destination, and source semantics verified
URL: https://nvd.nist.gov/vuln/detail/CVE-2026-72086
NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.
Supplemental references
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/1357fb32d42ad8da193e6da285f09e6452feabda
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/18d4f86816592586b38513543b5e1f9553bc271f
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/255fb7b0cdc947b1c01929c7f133281342a3a6b5
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/4567ce79fe2f84c3dcc3a91b22a377cf482d33ad
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/66aefc277ebb796ec285d550305535dc3fc0179f
416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/6c01f0439098f00a64b246dc27479602201382f7
416baaa9-dc9f-4396-8d5f-8c081fb06d67
-
Source reference
Unverified legacy reference
URL: https://git.kernel.org/stable/c/fbc1bdede66d0f2cde83b75d6524ce1a815bb69f
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Methodology and review provenance
AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.