CVE-2026-23375 (GCVE-0-2026-23375)

Vulnerability from cvelistv5 – Published: 2026-03-25 10:27 – Updated: 2026-03-25 10:27
VLAI?
Title
mm: thp: deny THP for files on anonymous inodes
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: thp: deny THP for files on anonymous inodes file_thp_enabled() incorrectly allows THP for files on anonymous inodes (e.g. guest_memfd and secretmem). These files are created via alloc_file_pseudo(), which does not call get_write_access() and leaves inode->i_writecount at 0. Combined with S_ISREG(inode->i_mode) being true, they appear as read-only regular files when CONFIG_READ_ONLY_THP_FOR_FS is enabled, making them eligible for THP collapse. Anonymous inodes can never pass the inode_is_open_for_write() check since their i_writecount is never incremented through the normal VFS open path. The right thing to do is to exclude them from THP eligibility altogether, since CONFIG_READ_ONLY_THP_FOR_FS was designed for real filesystem files (e.g. shared libraries), not for pseudo-filesystem inodes. For guest_memfd, this allows khugepaged and MADV_COLLAPSE to create large folios in the page cache via the collapse path, but the guest_memfd fault handler does not support large folios. This triggers WARN_ON_ONCE(folio_test_large(folio)) in kvm_gmem_fault_user_mapping(). For secretmem, collapse_file() tries to copy page contents through the direct map, but secretmem pages are removed from the direct map. This can result in a kernel crash: BUG: unable to handle page fault for address: ffff88810284d000 RIP: 0010:memcpy_orig+0x16/0x130 Call Trace: collapse_file hpage_collapse_scan_file madvise_collapse Secretmem is not affected by the crash on upstream as the memory failure recovery handles the failed copy gracefully, but it still triggers confusing false memory failure reports: Memory failure: 0x106d96f: recovery action for clean unevictable LRU page: Recovered Check IS_ANON_FILE(inode) in file_thp_enabled() to deny THP for all anonymous inode files.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 7fbb5e188248c50f737720825da1864ce42536d1 , < 08de46a75f91a6661bc1ce0a93614f4bc313c581 (git)
Affected: 7fbb5e188248c50f737720825da1864ce42536d1 , < 0524ee56af2c9bfbad152a810f1ca95de8ca00d7 (git)
Affected: 7fbb5e188248c50f737720825da1864ce42536d1 , < f6fa05f0dddd387417d0c28281ddb951582514d6 (git)
Affected: 7fbb5e188248c50f737720825da1864ce42536d1 , < dd085fe9a8ebfc5d10314c60452db38d2b75e609 (git)
Create a notification for this product.
    Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc2 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "08de46a75f91a6661bc1ce0a93614f4bc313c581",
              "status": "affected",
              "version": "7fbb5e188248c50f737720825da1864ce42536d1",
              "versionType": "git"
            },
            {
              "lessThan": "0524ee56af2c9bfbad152a810f1ca95de8ca00d7",
              "status": "affected",
              "version": "7fbb5e188248c50f737720825da1864ce42536d1",
              "versionType": "git"
            },
            {
              "lessThan": "f6fa05f0dddd387417d0c28281ddb951582514d6",
              "status": "affected",
              "version": "7fbb5e188248c50f737720825da1864ce42536d1",
              "versionType": "git"
            },
            {
              "lessThan": "dd085fe9a8ebfc5d10314c60452db38d2b75e609",
              "status": "affected",
              "version": "7fbb5e188248c50f737720825da1864ce42536d1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/huge_memory.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.78",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.17",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.7",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0-rc2",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: thp: deny THP for files on anonymous inodes\n\nfile_thp_enabled() incorrectly allows THP for files on anonymous inodes\n(e.g. guest_memfd and secretmem). These files are created via\nalloc_file_pseudo(), which does not call get_write_access() and leaves\ninode-\u003ei_writecount at 0. Combined with S_ISREG(inode-\u003ei_mode) being\ntrue, they appear as read-only regular files when\nCONFIG_READ_ONLY_THP_FOR_FS is enabled, making them eligible for THP\ncollapse.\n\nAnonymous inodes can never pass the inode_is_open_for_write() check\nsince their i_writecount is never incremented through the normal VFS\nopen path. The right thing to do is to exclude them from THP eligibility\naltogether, since CONFIG_READ_ONLY_THP_FOR_FS was designed for real\nfilesystem files (e.g. shared libraries), not for pseudo-filesystem\ninodes.\n\nFor guest_memfd, this allows khugepaged and MADV_COLLAPSE to create\nlarge folios in the page cache via the collapse path, but the\nguest_memfd fault handler does not support large folios. This triggers\nWARN_ON_ONCE(folio_test_large(folio)) in kvm_gmem_fault_user_mapping().\n\nFor secretmem, collapse_file() tries to copy page contents through the\ndirect map, but secretmem pages are removed from the direct map. This\ncan result in a kernel crash:\n\n    BUG: unable to handle page fault for address: ffff88810284d000\n    RIP: 0010:memcpy_orig+0x16/0x130\n    Call Trace:\n     collapse_file\n     hpage_collapse_scan_file\n     madvise_collapse\n\nSecretmem is not affected by the crash on upstream as the memory failure\nrecovery handles the failed copy gracefully, but it still triggers\nconfusing false memory failure reports:\n\n    Memory failure: 0x106d96f: recovery action for clean unevictable\n    LRU page: Recovered\n\nCheck IS_ANON_FILE(inode) in file_thp_enabled() to deny THP for all\nanonymous inode files."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-25T10:27:55.754Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/08de46a75f91a6661bc1ce0a93614f4bc313c581"
        },
        {
          "url": "https://git.kernel.org/stable/c/0524ee56af2c9bfbad152a810f1ca95de8ca00d7"
        },
        {
          "url": "https://git.kernel.org/stable/c/f6fa05f0dddd387417d0c28281ddb951582514d6"
        },
        {
          "url": "https://git.kernel.org/stable/c/dd085fe9a8ebfc5d10314c60452db38d2b75e609"
        }
      ],
      "title": "mm: thp: deny THP for files on anonymous inodes",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23375",
    "datePublished": "2026-03-25T10:27:55.754Z",
    "dateReserved": "2026-01-13T15:37:46.003Z",
    "dateUpdated": "2026-03-25T10:27:55.754Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23375\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-03-25T11:16:37.230\",\"lastModified\":\"2026-03-25T15:41:33.977\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm: thp: deny THP for files on anonymous inodes\\n\\nfile_thp_enabled() incorrectly allows THP for files on anonymous inodes\\n(e.g. guest_memfd and secretmem). These files are created via\\nalloc_file_pseudo(), which does not call get_write_access() and leaves\\ninode-\u003ei_writecount at 0. Combined with S_ISREG(inode-\u003ei_mode) being\\ntrue, they appear as read-only regular files when\\nCONFIG_READ_ONLY_THP_FOR_FS is enabled, making them eligible for THP\\ncollapse.\\n\\nAnonymous inodes can never pass the inode_is_open_for_write() check\\nsince their i_writecount is never incremented through the normal VFS\\nopen path. The right thing to do is to exclude them from THP eligibility\\naltogether, since CONFIG_READ_ONLY_THP_FOR_FS was designed for real\\nfilesystem files (e.g. shared libraries), not for pseudo-filesystem\\ninodes.\\n\\nFor guest_memfd, this allows khugepaged and MADV_COLLAPSE to create\\nlarge folios in the page cache via the collapse path, but the\\nguest_memfd fault handler does not support large folios. This triggers\\nWARN_ON_ONCE(folio_test_large(folio)) in kvm_gmem_fault_user_mapping().\\n\\nFor secretmem, collapse_file() tries to copy page contents through the\\ndirect map, but secretmem pages are removed from the direct map. This\\ncan result in a kernel crash:\\n\\n    BUG: unable to handle page fault for address: ffff88810284d000\\n    RIP: 0010:memcpy_orig+0x16/0x130\\n    Call Trace:\\n     collapse_file\\n     hpage_collapse_scan_file\\n     madvise_collapse\\n\\nSecretmem is not affected by the crash on upstream as the memory failure\\nrecovery handles the failed copy gracefully, but it still triggers\\nconfusing false memory failure reports:\\n\\n    Memory failure: 0x106d96f: recovery action for clean unevictable\\n    LRU page: Recovered\\n\\nCheck IS_ANON_FILE(inode) in file_thp_enabled() to deny THP for all\\nanonymous inode files.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0524ee56af2c9bfbad152a810f1ca95de8ca00d7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/08de46a75f91a6661bc1ce0a93614f4bc313c581\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/dd085fe9a8ebfc5d10314c60452db38d2b75e609\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f6fa05f0dddd387417d0c28281ddb951582514d6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.