Skip to content
Heist/ feed
Back to feed
UnratedFix available

ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.270, 5.15.221, 6.1.188, 6.12.110, 6.18.52, 6.6.157, 7.2.6
CVEs
CVE-2026-90303
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 16:22 UTC · Revision 1

Source evidence

ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults

core-osv · Original source

Published 17 Sept 2026, 16:08 UTC

In the Linux kernel, the following vulnerability has been resolved: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock.

osv:CVE-2026-90303

Kernel

Fixed versions: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6

Complete source record
{
  "id": "db57dc2c29a02a7e6ca603e3095476a2fab37c5b8de1efaa1cc66942755682cb",
  "url": "https://osv.dev/vulnerability/CVE-2026-90303",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline \"user_debug=31\" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the \"oops\" state, acquiring a lock may risk a deadlock.",
    "evidence": "osv:CVE-2026-90303",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.270",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.221",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.188",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.157",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.52",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-90303",
      "aliases": [
        "CVE-2026-90303"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6d021b724481fbb908eb29384898deb9f00dfe70"
                },
                {
                  "fixed": "ab14f07952adfe735d86a53518f8cd576dfd5892"
                },
                {
                  "fixed": "07e4d5380f2a844ab7a1b440dde350caf561cbb0"
                },
                {
                  "fixed": "2a14d7797a49a47bccd1a9327fd69da838dcb0dd"
                },
                {
                  "fixed": "63e3c958a602d0896a101a897c2361878c266ca7"
                },
                {
                  "fixed": "59bbf86d0ff9373bfa033ca123c1e924f09f1eba"
                },
                {
                  "fixed": "c71f9a56520b419e55d173052629f2324deb5549"
                },
                {
                  "fixed": "720408d98d9fb3c91a12090436734c8c61f04545"
                },
                {
                  "fixed": "1039bffd6ae9c75b42b7d148d6c1106134107b66"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90303.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.0.0"
                },
                {
                  "fixed": "5.10.270"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.221"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.188"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.157"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.110"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.52"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90303.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.320459324Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/07e4d5380f2a844ab7a1b440dde350caf561cbb0",
        "https://git.kernel.org/stable/c/1039bffd6ae9c75b42b7d148d6c1106134107b66",
        "https://git.kernel.org/stable/c/2a14d7797a49a47bccd1a9327fd69da838dcb0dd",
        "https://git.kernel.org/stable/c/59bbf86d0ff9373bfa033ca123c1e924f09f1eba",
        "https://git.kernel.org/stable/c/63e3c958a602d0896a101a897c2361878c266ca7",
        "https://git.kernel.org/stable/c/720408d98d9fb3c91a12090436734c8c61f04545",
        "https://git.kernel.org/stable/c/ab14f07952adfe735d86a53518f8cd576dfd5892",
        "https://git.kernel.org/stable/c/c71f9a56520b419e55d173052629f2324deb5549",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90303.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-90303",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90303.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-90303",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 497318,
  "published_at": "2026-09-17T16:08:26.455+00:00"
}