{"id":"CVE-2026-98900","title":"xen/gntalloc: validate grant count before allocation","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nxen/gntalloc: validate grant count before allocation\n\ngntalloc_ioctl_alloc() allocates the grant-id array before checking\nwhether the requested count fits within the gl…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 71a0cf87e19fb35c4292ca88985e376e613c900a","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 641de086a05f349de7fc548612432bc2fed721ca","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 720554c04acba80018ded069d3e0984bebaee891","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 84d5727cef8eb9c8a28210ad248f1c70b223b065","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 231542f4e43cf9837cb520664545e85fbe666b7b","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2299822f3f466b5dcad2377bf63986199f881a6b","Linux < 5.10.271","Linux < 5.15.222","Linux < 6.1.189","Linux < 6.6.158","Linux < 6.12.111","Linux < 6.18.53","Linux (all versions)"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T11:54:10.566Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98900","references":[{"url":"https://git.kernel.org/stable/c/e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8"},{"url":"https://git.kernel.org/stable/c/71a0cf87e19fb35c4292ca88985e376e613c900a"},{"url":"https://git.kernel.org/stable/c/641de086a05f349de7fc548612432bc2fed721ca"},{"url":"https://git.kernel.org/stable/c/720554c04acba80018ded069d3e0984bebaee891"},{"url":"https://git.kernel.org/stable/c/84d5727cef8eb9c8a28210ad248f1c70b223b065"},{"url":"https://git.kernel.org/stable/c/231542f4e43cf9837cb520664545e85fbe666b7b"},{"url":"https://git.kernel.org/stable/c/2299822f3f466b5dcad2377bf63986199f881a6b"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.574Z","slug":"CVE-2026-98900","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nxen/gntalloc: validate grant count before allocation\n\ngntalloc_ioctl_alloc() allocates the grant-id array before checking\nwhether the requested count fits within the global grant limit. Counts\nabove that limit cannot succeed, so reject them before the\nuser-controlled allocation reaches kcalloc().\n\nUse a subtraction-based check while holding gref_mutex so adding the\nrequested count cannot wrap. Also cast the count before advancing the\nper-file index so the page-size multiplication is performed in 64-bit\narithmetic.\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e2806390aa1c4d5b3f7a68f10a56ae12c71c00d8`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 71a0cf87e19fb35c4292ca88985e376e613c900a`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 641de086a05f349de7fc548612432bc2fed721ca`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 720554c04acba80018ded069d3e0984bebaee891`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 84d5727cef8eb9c8a28210ad248f1c70b223b065`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 231542f4e43cf9837cb520664545e85fbe666b7b`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2299822f3f466b5dcad2377bf63986199f881a6b`\n- `Linux < 5.10.271`\n- `Linux < 5.15.222`\n- `Linux < 6.1.189`\n- `Linux < 6.6.158`\n- `Linux < 6.12.111`\n- `Linux < 6.18.53`\n- `Linux (all versions)`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}