Description
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.
Published: 2026-03-25
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Kernel crash leading to denial of service
Action: Apply Patch
AI Analysis

Impact

The Linux arm64 kernel contains a defect in the GCS page‑mapping logic that triggers when FEAT_LPA2 is enabled. The code incorrectly sets the PTE_SHARED bits to 0b11, but under LPA2 these bits are overwritten by address bits, creating an invalid page‑table entry. This causes a kernel panic during a GCS write fault, halting the system or the affected process and resulting in a denial of service.

Affected Systems

ARM64 Linux kernels 6.13 and the 7.0.0‑rc1 through rc7 releases are affected. Systems that enable GCS and have the FEAT_LPA2 option active will experience the fault. This includes any deployment of these kernel versions on ARM64 hardware that relies on LPA2 support.

Risk and Exploitability

The CVSS score of 5.5 indicates moderate severity, and the EPSS score of less than 1% suggests a low likelihood of exploitation in the wild. The vulnerability is not listed in the CISA KEV catalog. Exploitation requires a GCS write fault, which normally occurs only on systems with FEAT_LPA2 enabled, making the attack vector likely local and the impact a forced kernel crash.

Generated by OpenCVE AI on April 29, 2026 at 01:59 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the kernel to a release that incorporates the GCS mapping fix. This is the official solution from the kernel maintainers.
  • If a patch is not yet available or a system upgrade is not feasible, disable the FEAT_LPA2 feature or turn off GCS functionality to prevent the panic from occurring.
  • Apply a temporary kernel patch that clears the PTE_SHARED field when FEAT_LPA2 is enabled, as described in the kernel commit referenced in the advisory.

Generated by OpenCVE AI on April 29, 2026 at 01:59 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Fri, 24 Apr 2026 18:30:00 +0000

Type Values Removed Values Added
Weaknesses NVD-CWE-noinfo
CPEs cpe:2.3:o:linux:linux_kernel:6.13:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*

Thu, 26 Mar 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Thu, 26 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-386
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Wed, 25 Mar 2026 22:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-284

Wed, 25 Mar 2026 10:45:00 +0000

Type Values Removed Values Added
Description 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.
Title arm64: gcs: Do not set PTE_SHARED on GCS mappings if FEAT_LPA2 is enabled
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T22:05:02.929Z

Reserved: 2026-01-13T15:37:45.999Z

Link: CVE-2026-23345

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2026-03-25T11:16:32.610

Modified: 2026-04-24T18:17:11.950

Link: CVE-2026-23345

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-25T00:00:00Z

Links: CVE-2026-23345 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-29T02:00:27Z

Weaknesses