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CVE-2026-64247— KVM: x86: hyper-v: Bound the bank index when querying sparse banks

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于未对VP ID进行边界检查，导致在查询稀疏银行时存在越界读取。

CVSS 8.4 · High EPSS 0.11% · P2

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux c58a318f6090efe06e6702b8882e2026f44f620e< d18756b12aab30d07794446445c93112e5c69a2e affected
c58a318f6090efe06e6702b8882e2026f44f620e< 83c2f52c6a78b1590034e955cff3fe0b052fe4ae affected
c58a318f6090efe06e6702b8882e2026f44f620e< e36095d8d922bb26ce860231aacf0cd14edea07c affected
c58a318f6090efe06e6702b8882e2026f44f620e< f636cf6a1e7b7f40d48d8d08bd5f152aa61dd130 affected
c58a318f6090efe06e6702b8882e2026f44f620e< 4721f8160f17554b003e8928bb61e6c9b2fe92a3 affected
6.2 affected
< 6.2 unaffected
6.6.144≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-64247

Vulnerability Information
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Vulnerability Title
KVM: x86: hyper-v: Bound the bank index when querying sparse banks
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: hyper-v: Bound the bank index when querying sparse banks When checking if a VP ID is included in a sparse bank set, explicitly check that the ID can actually be contained in a sparse bank (the TLFS allows for a maximum of 64 banks of 64 vCPUs each). When handling a paravirtual TLB flush for L2, the VP ID is copied verbatim from the enlightened VMCS, without any bounds check, i.e. isn't guaranteed to be under the limit of 4096. Failure to check the bounds of the VP ID leads to an out-of-bounds read when testing the sparse bank, and super strictly speaking could lead to KVM performing an unnecessary TLB flush for an L2 vCPU. ================================================================== BUG: KASAN: use-after-free in hv_is_vp_in_sparse_set+0x85/0x100 [kvm] Read of size 8 at addr ffff88811ba5f598 by task hyperv_evmcs/2802 CPU: 12 UID: 1000 PID: 2802 Comm: hyperv_evmcs Not tainted 7.1.0-rc2 #7 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x51/0x60 print_report+0xcb/0x5d0 kasan_report+0xb4/0xe0 kasan_check_range+0x35/0x1b0 hv_is_vp_in_sparse_set+0x85/0x100 [kvm] kvm_hv_flush_tlb+0xe9e/0x16c0 [kvm] kvm_hv_hypercall+0xe6b/0x1e60 [kvm] vmx_handle_exit+0x485/0x1b60 [kvm_intel] kvm_arch_vcpu_ioctl_run+0x22e3/0x5070 [kvm] kvm_vcpu_ioctl+0x5d0/0x10c0 [kvm] __x64_sys_ioctl+0x129/0x1a0 do_syscall_64+0xb9/0xcf0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f0e62d1a9bf </TASK> The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffffffffffffffff pfn:0x11ba5f flags: 0x4000000000000000(zone=1) raw: 4000000000000000 0000000000000000 00000000ffffffff 0000000000000000 raw: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88811ba5f480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88811ba5f500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88811ba5f580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88811ba5f600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88811ba5f680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Disabling lock debugging due to kernel taint Opportunistically add a compile time assertion to ensure the maximum number of sparse banks exactly matches the number of possible bits in the passed in mask. [sean: add KASAN splat, drop comment, add assert, massage changelog]
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于未对VP ID进行边界检查，导致在查询稀疏银行时存在越界读取。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux c58a318f6090efe06e6702b8882e2026f44f620e ~ d18756b12aab30d07794446445c93112e5c69a2e -
Linux Linux 6.2 -

II. Public POCs for CVE-2026-64247

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III. Intelligence Information for CVE-2026-64247

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Patches & Fixes for CVE-2026-64247 (5)

Same Patch Batch · Linux · 2026-07-24 · 48 CVEs total

CVE-2026-64232 9.8 CRITICAL block: recompute nr_integrity_segments in blk_insert_cloned_request
CVE-2026-64216 9.8 CRITICAL netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
CVE-2026-64255 8.8 HIGH wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers
CVE-2026-64223 8.1 HIGH wifi: mac80211: consume only present negotiated TTLM maps
CVE-2026-64235 8.1 HIGH x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines
CVE-2026-64218 7.8 HIGH batman-adv: bla: fix report_work leak on backbone_gw purge
CVE-2026-64226 7.8 HIGH sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path
CVE-2026-64221 7.8 HIGH spi: ti-qspi: fix use-after-free after DMA setup failure
CVE-2026-64251 7.8 HIGH pwrseq: core: fix use-after-free in pwrseq_debugfs_seq_next()
CVE-2026-64217 7.8 HIGH netfs: Fix overrun check in netfs_extract_user_iter()
CVE-2026-64208 7.5 HIGH crypto/krb5, rxrpc: Fix lack of pre-decrypt/pre-verify length checks
CVE-2026-64210 7.5 HIGH net/mlx5e: xsk: Fix unlocked writing to ICOSQ
CVE-2026-64243 7.1 HIGH ASoC: codecs: simple-mux: Fix enum control bounds check
CVE-2026-64222 7.0 HIGH octeontx2-pf: avoid double free of pool->stack on AQ init failure
CVE-2026-64219 7.0 HIGH drm/amd/display: Validate payload length and link_index in dc_process_dmub_aux_transfer_as
CVE-2026-64211 srcu: Don't queue workqueue handlers to never-online CPUs
CVE-2026-64225 octeontx2-af: CGX: add bounds check to cgx_speed_mbps index
CVE-2026-64212 wifi: iwlwifi: mld: don't dereference a pointer before NULL checking it
CVE-2026-64224 octeontx2-pf: fix double free in rvu_rep_rsrc_init()
CVE-2026-64209 phy: qcom: qmp-usbc: Fix out-of-bounds array access in dp swing config

Showing top 20 of 48 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-64247

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