CVE-2026-98900: Linux kernel · xen/gntalloc: validate grant count before allocation
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 01:29 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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
- ubuntu.com/security/CVE-2026-98900 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98900 (opens in a new tab)
- git.kernel.org/stable/c/2299822f3f466b5dcad2377bf63986199f881a6b (opens in a new tab)
- git.kernel.org/stable/c/231542f4e43cf9837cb520664545e85fbe666b7b (opens in a new tab)
- git.kernel.org/stable/c/641de086a05f349de7fc548612432bc2fed721ca (opens in a new tab)
- git.kernel.org/stable/c/71a0cf87e19fb35c4292ca88985e376e613c900a (opens in a new tab)
- git.kernel.org/stable/c/720554c04acba80018ded069d3e0984bebaee891 (opens in a new tab)
- git.kernel.org/stable/c/84d5727cef8eb9c8a28210ad248f1c70b223b065 (opens in a new tab)
- git.kernel.org/stable/c/e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8 (opens in a new tab)