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TI-2026-81862 Aliases CVE-2026-99155GHSA-p98p-xmcg-j23c

NULL pointer dereference in Linux kernel Xen SCSI frontend

Priority LOW 22Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
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Confidentiality · integrity · availability
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Fix status
Fixed

No CVSS vector from any source. Fix status from CNA.

Summary

The Linux kernel xen/scsifront SCSI frontend driver is affected from 5.19 before the fixed versions. The scsifront_do_response() function uses a backend response's request id to index a shadow slot without checking that the slot is populated, which leads to a NULL pointer dereference. A malicious or buggy backend can crash the guest by sending a response with an in-range request id that is not in flight, such as a spurious or duplicate response.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

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.

Why it matters now

EPSS 0.00187 8th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 6.1.191, 6.6.161, 6.12.115 +3

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.19 and later6.1.191, 6.6.161, 6.12.115, 6.18.59, 7.2.13, 7.3Patch availableCNA
  • Linux VendorLinux Affected 5.19 and later Fixed in 6.1.191, 6.6.161, 6.12.115, 6.18.59, 7.2.13, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Update the Linux kernel to 6.1.191, 6.6.161, 6.12.115, 6.18.59, 7.2.13, or 7.3, depending on the release branch in use.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

  • Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.161, 6.12.115, 6.18.59, 7.2.13, 7.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 7 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-28 Threatist record created from CVE-2026-99155
  2. 2026-10-28 Alias added: GHSA-p98p-xmcg-j23c
  3. 2026-10-30 Fix available: Linux/Linux@448b9a8b530b753d346dab10add09a502fc719a4, Linux/[email protected], Linux/[email protected] +3 · CNA
  4. 2026-10-30 3 new references · CNA
  5. 2026-11-01 Affected versions changed · Red Hat
  6. 2026-11-01 CVSS score added · Red Hat
  7. 2026-11-02 Affected versions changed · Red Hat

References

Other 6

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences