CVE intelligence

CVE-2026-99155

Vulnerability intelligence

Published Oct 28, 2026Sources checked Oct 28, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-99155. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 29, 2026

Release Notes

CISA KEVNot listedBased on the latest collected catalog

EPSSUnavailableNo current score collected

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-99155?

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.

Source: NVD