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CVE-2022-49778— arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud

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，该漏洞源于页表计数错误，可能导致崩溃。

AI Predicted 4.3 Difficulty: Theoretical EPSS 0.16% · P5

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux 42b2547137f5c974bb1bfd657c869fe96b96d86f< 2d458046df634088611d44fd77f45465e833ef78 affected
42b2547137f5c974bb1bfd657c869fe96b96d86f< 5b47348fc0b18a78c96f8474cc90b7525ad1bbfe affected
5.19 affected
< 5.19 unaffected
6.0.10≤ 6.0.* unaffected
6.1≤ * unaffected
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I. Basic Information for CVE-2022-49778

Vulnerability Information
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Vulnerability Title
arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: arm64/mm: fix incorrect file_map_count for non-leaf pmd/pud The page table check trigger BUG_ON() unexpectedly when collapse hugepage: ------------[ cut here ]------------ kernel BUG at mm/page_table_check.c:82! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 6 PID: 68 Comm: khugepaged Not tainted 6.1.0-rc3+ #750 Hardware name: linux,dummy-virt (DT) pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : page_table_check_clear.isra.0+0x258/0x3f0 lr : page_table_check_clear.isra.0+0x240/0x3f0 [...] Call trace: page_table_check_clear.isra.0+0x258/0x3f0 __page_table_check_pmd_clear+0xbc/0x108 pmdp_collapse_flush+0xb0/0x160 collapse_huge_page+0xa08/0x1080 hpage_collapse_scan_pmd+0xf30/0x1590 khugepaged_scan_mm_slot.constprop.0+0x52c/0xac8 khugepaged+0x338/0x518 kthread+0x278/0x2f8 ret_from_fork+0x10/0x20 [...] Since pmd_user_accessible_page() doesn't check if a pmd is leaf, it decrease file_map_count for a non-leaf pmd comes from collapse_huge_page(). and so trigger BUG_ON() unexpectedly. Fix this problem by using pmd_leaf() insteal of pmd_present() in pmd_user_accessible_page(). Moreover, use pud_leaf() for pud_user_accessible_page() too.
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，该漏洞源于页表计数错误，可能导致崩溃。
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 42b2547137f5c974bb1bfd657c869fe96b96d86f ~ 2d458046df634088611d44fd77f45465e833ef78 -
Linux Linux 5.19 -

II. Public POCs for CVE-2022-49778

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III. Intelligence Information for CVE-2022-49778

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Patches & Fixes for CVE-2022-49778 (2)

Same Patch Batch · Linux · 2025-05-01 · 245 CVEs total

CVE-2025-37750 9.8 CRITICAL smb: client: fix UAF in decryption with multichannel
CVE-2025-37778 9.8 CRITICAL ksmbd: Fix dangling pointer in krb_authenticate
CVE-2022-49770 9.8 CRITICAL ceph: avoid putting the realm twice when decoding snaps fails
CVE-2022-49931 8.8 HIGH IB/hfi1: Correctly move list in sc_disable()
CVE-2025-37776 8.8 HIGH ksmbd: fix use-after-free in smb_break_all_levII_oplock()
CVE-2025-37777 8.8 HIGH ksmbd: fix use-after-free in __smb2_lease_break_noti()
CVE-2025-37790 8.8 HIGH net: mctp: Set SOCK_RCU_FREE
CVE-2022-49910 8.8 HIGH Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu
CVE-2022-49886 8.4 HIGH x86/tdx: Panic on bad configs that #VE on "private" memory access
CVE-2025-23159 8.4 HIGH media: venus: hfi: add a check to handle OOB in sfr region
CVE-2025-37749 8.2 HIGH net: ppp: Add bound checking for skb data on ppp_sync_txmung
CVE-2025-37765 7.8 HIGH drm/nouveau: prime: fix ttm_bo_delayed_delete oops
CVE-2025-37779 7.8 HIGH lib/iov_iter: fix to increase non slab folio refcount
CVE-2022-49920 7.8 HIGH netfilter: nf_tables: netlink notifier might race to release objects
CVE-2022-49919 7.8 HIGH netfilter: nf_tables: release flow rule object from commit path
CVE-2022-49921 7.8 HIGH net: sched: Fix use after free in red_enqueue()
CVE-2025-37752 7.8 HIGH net_sched: sch_sfq: move the limit validation
CVE-2025-37756 7.8 HIGH net: tls: explicitly disallow disconnect
CVE-2025-37761 7.8 HIGH drm/xe: Fix an out-of-bounds shift when invalidating TLB
CVE-2022-49804 7.8 HIGH s390: avoid using global register for current_stack_pointer

Showing top 20 of 245 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2022-49778

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