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CVE-2026-99155

Опубликовано: 28 окт. 2026
Источник: redhat
CVSS3: 4.4

Описание

In the Linux kernel, the following vulnerability has been resolved: scsi: xen/scsifront: Check for a NULL shadow entry on a backend response scsifront_do_response() validates the rqid in a backend response against VSCSIIF_MAX_REQS before using it to index info->shadow[], but then dereferences the entry to test ->inflight without checking that the slot is populated. Shadow slots are NULL before a command is submitted (the host private area is zeroed at allocation) and are reset to NULL in _scsifront_put_rqid() once a request completes, so an in-range rqid that does not correspond to an outstanding request makes the frontend dereference a NULL pointer. A malicious or buggy backend can thus crash the guest by returning a response whose rqid is in range but not in flight -- for example a spurious response before any command has been issued, or a duplicate of one already completed. The ring has only VSCSIIF_MAX_REQS (16) slots, so before the first command every in-range rqid selects a NULL slot. Reject a response whose shadow slot is not populated.

A flaw was found in the Linux kernel's Xen virtual Small Computer System Interface (SCSI) frontend driver. This vulnerability allows a malicious or compromised backend service to trigger a Denial of Service (DoS) by crashing the guest virtual machine. The issue occurs when the driver processes a storage response referencing an inactive request identifier, causing the system to dereference an unpopulated pointer due to missing validation.

Отчет

This vulnerability is classified as having Moderate severity because exploitation requires elevated host privileges or a compromised Xen backend domain, restricting exposure exclusively to Xen-virtualized guests using virtual SCSI devices. In standard Red Hat Enterprise Linux environments, virtualization primarily utilizes KVM with virtio storage rather than Xen paravirtualized SCSI drivers. Furthermore, triggering the unpopulated pointer dereference results only in a guest denial of service without permitting arbitrary code execution or data leakage.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Enterprise Linux 10kernelNot affected
Red Hat Enterprise Linux 6kernelNot affected
Red Hat Enterprise Linux 7kernelNot affected
Red Hat Enterprise Linux 7kernel-rtNot affected
Red Hat Enterprise Linux 8kernelNot affected
Red Hat Enterprise Linux 8kernel-rtNot affected
Red Hat Enterprise Linux 9kernelNot affected
Red Hat Enterprise Linux 9kernel-rtNot affected
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-8Not affected
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-9Not affected

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Дополнительная информация

Статус:

Moderate
Дефект:
CWE-476
https://bugzilla.redhat.com/show_bug.cgi?id=2562717kernel: kernel: xen-scsifront: Denial of Service via NULL pointer dereference

4.4 Medium

CVSS3

Связанные уязвимости

ubuntu
11 дней назад

In the Linux kernel, the following vulnerability has been resolved: scsi: xen/scsifront: Check for a NULL shadow entry on a backend response scsifront_do_response() validates the rqid in a backend response against VSCSIIF_MAX_REQS before using it to index info->shadow[], but then dereferences the entry to test ->inflight without checking that the slot is populated. Shadow slots are NULL before a command is submitted (the host private area is zeroed at allocation) and are reset to NULL in _scsifront_put_rqid() once a request completes, so an in-range rqid that does not correspond to an outstanding request makes the frontend dereference a NULL pointer. A malicious or buggy backend can thus crash the guest by returning a response whose rqid is in range but not in flight -- for example a spurious response before any command has been issued, or a duplicate of one already completed. The ring has only VSCSIIF_MAX_REQS (16) slots, so before the first command every in-range rqid selects a ...

nvd
11 дней назад

In the Linux kernel, the following vulnerability has been resolved: scsi: xen/scsifront: Check for a NULL shadow entry on a backend response scsifront_do_response() validates the rqid in a backend response against VSCSIIF_MAX_REQS before using it to index info->shadow[], but then dereferences the entry to test ->inflight without checking that the slot is populated. Shadow slots are NULL before a command is submitted (the host private area is zeroed at allocation) and are reset to NULL in _scsifront_put_rqid() once a request completes, so an in-range rqid that does not correspond to an outstanding request makes the frontend dereference a NULL pointer. A malicious or buggy backend can thus crash the guest by returning a response whose rqid is in range but not in flight -- for example a spurious response before any command has been issued, or a duplicate of one already completed. The ring has only VSCSIIF_MAX_REQS (16) slots, so before the first command every in-range rqid selects a

CVSS3: 5.5
msrc
3 дня назад

scsi: xen/scsifront: Check for a NULL shadow entry on a backend response

debian
11 дней назад

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

github
11 дней назад

In the Linux kernel, the following vulnerability has been resolved: scsi: xen/scsifront: Check for a NULL shadow entry on a backend response scsifront_do_response() validates the rqid in a backend response against VSCSIIF_MAX_REQS before using it to index info->shadow[], but then dereferences the entry to test ->inflight without checking that the slot is populated. Shadow slots are NULL before a command is submitted (the host private area is zeroed at allocation) and are reset to NULL in _scsifront_put_rqid() once a request completes, so an in-range rqid that does not correspond to an outstanding request makes the frontend dereference a NULL pointer. A malicious or buggy backend can thus crash the guest by returning a response whose rqid is in range but not in flight -- for example a spurious response before any command has been issued, or a duplicate of one already completed. The ring has only VSCSIIF_MAX_REQS (16) slots, so before the first command every in-range rqid selects...

4.4 Medium

CVSS3