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mm: filemap: fix nr_pages calculation overflow in filemap_map_pages()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: mm: filemap: fix nr_pages calculation overflow in filemap_map_pages() When running stress-ng on my Arm64 machine with v7.0-rc3 kernel, I encountered some very strange crash issues showing up as "Bad page state": " [ 734.496287] BUG: Bad page state in process stress-ng-env pfn:415735fb [ 734.496427] page: refcount:0 mapcount:1 mapping:0000000000000000 index:0x4cf316 pfn:0x415735fb [ 734.496434] flags: 0x57fffe000000800(owner_2|node=1|zone=2|lastcpupid=0x3ffff) [ 734.496439] raw: 057fffe000000800 0000000000000000 dead000000000122 0000000000000000 [ 734.496440] raw: 00000000004cf316 0000000000000000 0000000000000000 0000000000000000 [ 734.496442] page dumped because: nonzero mapcount " After analyzing this page’s state, it is hard to understand why the mapcount is not 0 while the refcount is 0, since this page is not where the issue first occurred. By enabling the CONFIG_DEBUG_VM config, I can reproduce the crash as well and captured the first warning where the issue appears: " [ 734.469226] page: refcount:33 mapcount:0 mapping:00000000bef2d187 index:0x81a0 pfn:0x415735c0 [ 734.469304] head: order:5 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 [ 734.469315] memcg:ffff000807a8ec00 [ 734.469320] aops:ext4_da_aops ino:100b6f dentry name(?):"stress-ng-mmaptorture-9397-0-2736200540" [ 734.469335] flags: 0x57fffe400000069(locked|uptodate|lru|head|node=1|zone=2|lastcpupid=0x3ffff) ...... [ 734.469364] page

Announced Source revision 1
Original source ↗

CVE-2026-31648

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-31648

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "fe601b70eac6cd266e8d7d55030e90a73ed0e339",
        "lessThan": "88591194df736a508dd5461ab2167a61e98caac1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "743a2753a02e805347969f6f89f38b736850d808",
        "lessThan": "633ab680c405ac390e6bec5b74aaf46197c837b6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "743a2753a02e805347969f6f89f38b736850d808",
        "lessThan": "576543bedd616254032d4ebe54a90076f9e31740",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "743a2753a02e805347969f6f89f38b736850d808",
        "lessThan": "9316a820b9aae07d44469d6485376dad824c5b3f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "743a2753a02e805347969f6f89f38b736850d808",
        "lessThan": "f58df566524ebcdfa394329c64f47e3c9257516e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "84ede15f27c06b111d1398dfa80b6fac4b135e34",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.6.117",
        "lessThan": "6.6.135",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.159",
        "lessThan": "6.2",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "mm/filemap.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.12"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.12",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.135",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.82",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.23",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.13",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "mm/filemap.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-31648

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#39936 · Revision 1
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Publisher date
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