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CVE-2021-47230— KVM: x86: Immediately reset the MMU context when the SMM flag is cleared

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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于当SMM标志被清除时没有立即重置MMU环境。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.23% · P13

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 9ec19493fb86d6d5fbf9286b94ff21e56ef66376< cbb425f62df9df7abee4b3f068f7ed6ffc3561e2 affected
9ec19493fb86d6d5fbf9286b94ff21e56ef66376< 669a8866e468fd020d34eb00e08cb41d3774b71b affected
9ec19493fb86d6d5fbf9286b94ff21e56ef66376< df9a40cfb3be2cbeb1c17bb67c59251ba16630f3 affected
9ec19493fb86d6d5fbf9286b94ff21e56ef66376< 78fcb2c91adfec8ce3a2ba6b4d0dda89f2f4a7c6 affected
5.1 affected
< 5.1 unaffected
5.4.128≤ 5.4.* unaffected
5.10.46≤ 5.10.* unaffected
… +2 more rows
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I. Basic Information for CVE-2021-47230

Vulnerability Information
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Vulnerability Title
KVM: x86: Immediately reset the MMU context when the SMM flag is cleared
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Immediately reset the MMU context when the SMM flag is cleared Immediately reset the MMU context when the vCPU's SMM flag is cleared so that the SMM flag in the MMU role is always synchronized with the vCPU's flag. If RSM fails (which isn't correctly emulated), KVM will bail without calling post_leave_smm() and leave the MMU in a bad state. The bad MMU role can lead to a NULL pointer dereference when grabbing a shadow page's rmap for a page fault as the initial lookups for the gfn will happen with the vCPU's SMM flag (=0), whereas the rmap lookup will use the shadow page's SMM flag, which comes from the MMU (=1). SMM has an entirely different set of memslots, and so the initial lookup can find a memslot (SMM=0) and then explode on the rmap memslot lookup (SMM=1). general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 8410 Comm: syz-executor382 Not tainted 5.13.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__gfn_to_rmap arch/x86/kvm/mmu/mmu.c:935 [inline] RIP: 0010:gfn_to_rmap+0x2b0/0x4d0 arch/x86/kvm/mmu/mmu.c:947 Code: <42> 80 3c 20 00 74 08 4c 89 ff e8 f1 79 a9 00 4c 89 fb 4d 8b 37 44 RSP: 0018:ffffc90000ffef98 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888015b9f414 RCX: ffff888019669c40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: ffffffff811d9cdb R09: ffffed10065a6002 R10: ffffed10065a6002 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000003 R14: 0000000000000001 R15: 0000000000000000 FS: 000000000124b300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000028e31000 CR4: 00000000001526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rmap_add arch/x86/kvm/mmu/mmu.c:965 [inline] mmu_set_spte+0x862/0xe60 arch/x86/kvm/mmu/mmu.c:2604 __direct_map arch/x86/kvm/mmu/mmu.c:2862 [inline] direct_page_fault+0x1f74/0x2b70 arch/x86/kvm/mmu/mmu.c:3769 kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:124 [inline] kvm_mmu_page_fault+0x199/0x1440 arch/x86/kvm/mmu/mmu.c:5065 vmx_handle_exit+0x26/0x160 arch/x86/kvm/vmx/vmx.c:6122 vcpu_enter_guest+0x3bdd/0x9630 arch/x86/kvm/x86.c:9428 vcpu_run+0x416/0xc20 arch/x86/kvm/x86.c:9494 kvm_arch_vcpu_ioctl_run+0x4e8/0xa40 arch/x86/kvm/x86.c:9722 kvm_vcpu_ioctl+0x70f/0xbb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3460 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x440ce9
Source: CVE Program / CVE List V5
CVSS Information
N/A
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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于当SMM标志被清除时没有立即重置MMU环境。
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 9ec19493fb86d6d5fbf9286b94ff21e56ef66376 ~ cbb425f62df9df7abee4b3f068f7ed6ffc3561e2 -
Linux Linux 5.1 -

II. Public POCs for CVE-2021-47230

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III. Intelligence Information for CVE-2021-47230

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Other References for CVE-2021-47230 (3)

Same Patch Batch · Linux · 2024-05-21 · 361 CVEs total

CVE-2023-52741 9.8 CRITICAL cifs: Fix use-after-free in rdata->read_into_pages()
CVE-2023-52755 9.8 CRITICAL ksmbd: fix slab out of bounds write in smb_inherit_dacl()
CVE-2021-47378 9.8 CRITICAL nvme-rdma: destroy cm id before destroy qp to avoid use after free
CVE-2021-47427 9.8 CRITICAL scsi: iscsi: Fix iscsi_task use after free
CVE-2023-52732 9.8 CRITICAL ceph: blocklist the kclient when receiving corrupted snap trace
CVE-2021-47232 9.8 CRITICAL can: j1939: fix Use-after-Free, hold skb ref while in use
CVE-2021-47328 9.8 CRITICAL scsi: iscsi: Fix conn use after free during resets
CVE-2023-52769 8.8 HIGH wifi: ath12k: fix htt mlo-offset event locking
CVE-2023-52790 8.8 HIGH swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC
CVE-2021-47308 8.8 HIGH scsi: libfc: Fix array index out of bound exception
CVE-2021-47390 8.8 HIGH KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()
CVE-2023-52798 8.8 HIGH wifi: ath11k: fix dfs radar event locking
CVE-2021-47388 8.8 HIGH mac80211: fix use-after-free in CCMP/GCMP RX
CVE-2023-52776 8.8 HIGH wifi: ath12k: fix dfs-radar and temperature event locking
CVE-2023-52801 8.8 HIGH iommufd: Fix missing update of domains_itree after splitting iopt_area
CVE-2023-52846 8.8 HIGH hsr: Prevent use after free in prp_create_tagged_frame()
CVE-2021-47352 8.4 HIGH virtio-net: Add validation for used length
CVE-2023-52829 8.4 HIGH wifi: ath12k: fix possible out-of-bound write in ath12k_wmi_ext_hal_reg_caps()
CVE-2021-47240 8.4 HIGH net: qrtr: fix OOB Read in qrtr_endpoint_post
CVE-2021-47244 8.2 HIGH mptcp: Fix out of bounds when parsing TCP options

Showing top 20 of 361 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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