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.
- Status
- Received - 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- Published
- 2026-10-28
- Last modified
- 2026-10-28
Affected products
References
- https://git.kernel.org/stable/c/1d91ec793d6c80eca963d426e0da832d40a062df
- https://git.kernel.org/stable/c/15791e57f57f7050014d08cfe239d4aa1e6b94b0
- https://git.kernel.org/stable/c/8c8222c255772713eb36cde695777a1fce224917
