CVE-2026-98900

high

Description

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.

References

https://git.kernel.org/stable/c/e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8

https://git.kernel.org/stable/c/84d5727cef8eb9c8a28210ad248f1c70b223b065

https://git.kernel.org/stable/c/720554c04acba80018ded069d3e0984bebaee891

https://git.kernel.org/stable/c/71a0cf87e19fb35c4292ca88985e376e613c900a

https://git.kernel.org/stable/c/641de086a05f349de7fc548612432bc2fed721ca

https://git.kernel.org/stable/c/231542f4e43cf9837cb520664545e85fbe666b7b

https://git.kernel.org/stable/c/2299822f3f466b5dcad2377bf63986199f881a6b

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-108856

Details

Source: Mitre, NVD

Published: 2026-10-23

Updated: 2026-10-23

Risk Information

CVSS v2

Base Score: 5.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 7.8

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity: High