Live › vulnerability › CVE-2026-99155
Go to dashboardThe Xen SCSI frontend in the Linux kernel dereferences a NULL shadow entry when the backend sends a response whose request ID has no outstanding request. A malicious or buggy Xen backend can crash the guest kernel with this response.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-28 11:32 UTC. All times on this page are UTC.
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Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
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.
This page as .md · .json · in your agent: get_signal("CVE-2026-99155")
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