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TI-2026-79657 Aliases CVE-2026-98900GHSA-mwrq-hx54-3h97

Linux xen/gntalloc driver allocates before checking grant count

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/gntalloc driver is affected from 2.6.39 onward, with fixes listed per stable branch. The gntalloc_ioctl_alloc() function allocates the grant-id array before checking the requested count against the global grant limit, so a user-controlled count reaches the allocation. Counts above the limit cannot succeed, but they are still allocated first.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: xen/gntalloc: validate grant count before allocation gntalloc_ioctl_alloc() allocates the grant-id array before checking whether the requested count fits within the global grant limit. Counts above that limit cannot succeed, so reject them before the user-controlled allocation reaches kcalloc(). Use a subtraction-based check while holding gref_mutex so adding the requested count cannot wrap. Also cast the count before advancing the per-file index so the page-size multiplication is performed in 64-bit arithmetic.

Why it matters now

EPSS 0.00179 7th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 5.10.271, 5.15.222, 6.1.189 +4

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.39 and later5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2Patch availableCNA
  • Linux VendorLinux Affected 2.6.39 and later Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2 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 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53 or 7.2, or to a kernel that includes the fixing commits in the affected ranges.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2

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. 2026-10-23 Threatist record created from CVE-2026-98900
  2. 2026-10-23 Alias added: GHSA-mwrq-hx54-3h97
  3. 2026-10-26 Fix available: Linux/Linux@0 · CNA
  4. 2026-10-26 Affected versions changed · Red Hat
  5. 2026-10-26 CVSS score added · Red Hat
  6. 2026-11-06 Affected versions changed · Red Hat

References

Other 7

  • 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 21727 →

Sources

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