{"cve":"CVE-2026-23345","nvd":{"published":"2026-03-25T11:16:32.610","modified":"2026-06-17T10:21:23.707","status":"Analyzed","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/1df3ef7e612d6ccbae5a48e1121553c47c2123d6","https://git.kernel.org/stable/c/8a85b3131225a8c8143ba2ae29c0eef8c1f9117f","https://git.kernel.org/stable/c/ca1684dd297bf0725c1d487cff80e615497accf6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-23345","score":0.00125,"percentile":0.02213,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}