GHSA-67RR-WM48-F5VP

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-03-25 12:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

arm64: gcs: Do not set PTE_SHARED on GCS mappings if FEAT_LPA2 is enabled

When FEAT_LPA2 is enabled, bits 8-9 of the PTE replace the shareability attribute with bits 50-51 of the output address. The PAGE_GCS{,_RO} definitions include the PTE_SHARED bits as 0b11 (this matches the other _PAGE* definitions) but using this macro directly leads to the following panic when enabling GCS on a system/model with LPA2:

Unable to handle kernel paging request at virtual address fffff1ffc32d8008 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 swapper pgtable: 4k pages, 52-bit VAs, pgdp=0000000060f4d000 [fffff1ffc32d8008] pgd=100000006184b003, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP CPU: 0 UID: 0 PID: 513 Comm: gcs_write_fault Tainted: G M 7.0.0-rc1 #1 PREEMPT Tainted: [M]=MACHINE_CHECK Hardware name: QEMU QEMU Virtual Machine, BIOS 2025.02-8+deb13u1 11/08/2025 pstate: 03402005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : zap_huge_pmd+0x168/0x468 lr : zap_huge_pmd+0x2c/0x468 sp : ffff800080beb660 x29: ffff800080beb660 x28: fff00000c2058180 x27: ffff800080beb898 x26: fff00000c2058180 x25: ffff800080beb820 x24: 00c800010b600f41 x23: ffffc1ffc30af1a8 x22: fff00000c2058180 x21: 0000ffff8dc00000 x20: fff00000c2bc6370 x19: ffff800080beb898 x18: ffff800080bebb60 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000007 x14: 000000000000000a x13: 0000aaaacbbbffff x12: 0000000000000000 x11: 0000ffff8ddfffff x10: 00000000000001fe x9 : 0000ffff8ddfffff x8 : 0000ffff8de00000 x7 : 0000ffff8da00000 x6 : fff00000c2bc6370 x5 : 0000ffff8da00000 x4 : 000000010b600000 x3 : ffffc1ffc0000000 x2 : fff00000c2058180 x1 : fffff1ffc32d8000 x0 : 000000c00010b600 Call trace: zap_huge_pmd+0x168/0x468 (P) unmap_page_range+0xd70/0x1560 unmap_single_vma+0x48/0x80 unmap_vmas+0x90/0x180 unmap_region+0x88/0xe4 vms_complete_munmap_vmas+0xf8/0x1e0 do_vmi_align_munmap+0x158/0x180 do_vmi_munmap+0xac/0x160 __vm_munmap+0xb0/0x138 vm_munmap+0x14/0x20 gcs_free+0x70/0x80 mm_release+0x1c/0xc8 exit_mm_release+0x28/0x38 do_exit+0x190/0x8ec do_group_exit+0x34/0x90 get_signal+0x794/0x858 arch_do_signal_or_restart+0x11c/0x3e0 exit_to_user_mode_loop+0x10c/0x17c el0_da+0x8c/0x9c el0t_64_sync_handler+0xd0/0xf0 el0t_64_sync+0x198/0x19c Code: aa1603e2 d34cfc00 cb813001 8b011861 (f9400420)

Similarly to how the kernel handles protection_map[], use a gcs_page_prot variable to store the protection bits and clear PTE_SHARED if LPA2 is enabled.

Also remove the unused PAGE_GCS{,_RO} macros.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23345"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-25T11:16:32Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: gcs: Do not set PTE_SHARED on GCS mappings if FEAT_LPA2 is enabled\n\nWhen FEAT_LPA2 is enabled, bits 8-9 of the PTE replace the\nshareability attribute with bits 50-51 of the output address. The\n_PAGE_GCS{,_RO} definitions include the PTE_SHARED bits as 0b11 (this\nmatches the other _PAGE_* definitions) but using this macro directly\nleads to the following panic when enabling GCS on a system/model with\nLPA2:\n\n  Unable to handle kernel paging request at virtual address fffff1ffc32d8008\n  Mem abort info:\n    ESR = 0x0000000096000004\n    EC = 0x25: DABT (current EL), IL = 32 bits\n    SET = 0, FnV = 0\n    EA = 0, S1PTW = 0\n    FSC = 0x04: level 0 translation fault\n  Data abort info:\n    ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000\n    CM = 0, WnR = 0, TnD = 0, TagAccess = 0\n    GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0\n  swapper pgtable: 4k pages, 52-bit VAs, pgdp=0000000060f4d000\n  [fffff1ffc32d8008] pgd=100000006184b003, p4d=0000000000000000\n  Internal error: Oops: 0000000096000004 [#1]  SMP\n  CPU: 0 UID: 0 PID: 513 Comm: gcs_write_fault Tainted: G   M                7.0.0-rc1 #1 PREEMPT\n  Tainted: [M]=MACHINE_CHECK\n  Hardware name: QEMU QEMU Virtual Machine, BIOS 2025.02-8+deb13u1 11/08/2025\n  pstate: 03402005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)\n  pc : zap_huge_pmd+0x168/0x468\n  lr : zap_huge_pmd+0x2c/0x468\n  sp : ffff800080beb660\n  x29: ffff800080beb660 x28: fff00000c2058180 x27: ffff800080beb898\n  x26: fff00000c2058180 x25: ffff800080beb820 x24: 00c800010b600f41\n  x23: ffffc1ffc30af1a8 x22: fff00000c2058180 x21: 0000ffff8dc00000\n  x20: fff00000c2bc6370 x19: ffff800080beb898 x18: ffff800080bebb60\n  x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000007\n  x14: 000000000000000a x13: 0000aaaacbbbffff x12: 0000000000000000\n  x11: 0000ffff8ddfffff x10: 00000000000001fe x9 : 0000ffff8ddfffff\n  x8 : 0000ffff8de00000 x7 : 0000ffff8da00000 x6 : fff00000c2bc6370\n  x5 : 0000ffff8da00000 x4 : 000000010b600000 x3 : ffffc1ffc0000000\n  x2 : fff00000c2058180 x1 : fffff1ffc32d8000 x0 : 000000c00010b600\n  Call trace:\n   zap_huge_pmd+0x168/0x468 (P)\n   unmap_page_range+0xd70/0x1560\n   unmap_single_vma+0x48/0x80\n   unmap_vmas+0x90/0x180\n   unmap_region+0x88/0xe4\n   vms_complete_munmap_vmas+0xf8/0x1e0\n   do_vmi_align_munmap+0x158/0x180\n   do_vmi_munmap+0xac/0x160\n   __vm_munmap+0xb0/0x138\n   vm_munmap+0x14/0x20\n   gcs_free+0x70/0x80\n   mm_release+0x1c/0xc8\n   exit_mm_release+0x28/0x38\n   do_exit+0x190/0x8ec\n   do_group_exit+0x34/0x90\n   get_signal+0x794/0x858\n   arch_do_signal_or_restart+0x11c/0x3e0\n   exit_to_user_mode_loop+0x10c/0x17c\n   el0_da+0x8c/0x9c\n   el0t_64_sync_handler+0xd0/0xf0\n   el0t_64_sync+0x198/0x19c\n  Code: aa1603e2 d34cfc00 cb813001 8b011861 (f9400420)\n\nSimilarly to how the kernel handles protection_map[], use a\ngcs_page_prot variable to store the protection bits and clear PTE_SHARED\nif LPA2 is enabled.\n\nAlso remove the unused PAGE_GCS{,_RO} macros.",
  "id": "GHSA-67rr-wm48-f5vp",
  "modified": "2026-03-25T12:30:23Z",
  "published": "2026-03-25T12:30:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23345"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1df3ef7e612d6ccbae5a48e1121553c47c2123d6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8a85b3131225a8c8143ba2ae29c0eef8c1f9117f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ca1684dd297bf0725c1d487cff80e615497accf6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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