cve/published/2025/CVE-2025-21696.json

{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: clear uffd-wp PTE/PMD state on mremap()\n\nWhen mremap()ing a memory region previously registered with userfaultfd as\nwrite-protected but without UFFD_FEATURE_EVENT_REMAP, an inconsistency in\nflag clearing leads to a mismatch between the vma flags (which have\nuffd-wp cleared) and the pte/pmd flags (which do not have uffd-wp\ncleared).  This mismatch causes a subsequent mprotect(PROT_WRITE) to\ntrigger a warning in page_table_check_pte_flags() due to setting the pte\nto writable while uffd-wp is still set.\n\nFix this by always explicitly clearing the uffd-wp pte/pmd flags on any\nsuch mremap() so that the values are consistent with the existing clearing\nof VM_UFFD_WP.  Be careful to clear the logical flag regardless of its\nphysical form; a PTE bit, a swap PTE bit, or a PTE marker.  Cover PTE,\nhuge PMD and hugetlb paths."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "include/linux/userfaultfd_k.h",
                  "mm/huge_memory.c",
                  "mm/hugetlb.c",
                  "mm/mremap.c"
               ],
               "versions": [
                  {
                     "version": "63b2d4174c4ad1f40b48d7138e71bcb564c1fe03",
                     "lessThan": "310ac886d68de661c3a334198d8604b722d7fdf8",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "63b2d4174c4ad1f40b48d7138e71bcb564c1fe03",
                     "lessThan": "0cef0bb836e3cfe00f08f9606c72abd72fe78ca3",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "include/linux/userfaultfd_k.h",
                  "mm/huge_memory.c",
                  "mm/hugetlb.c",
                  "mm/mremap.c"
               ],
               "versions": [
                  {
                     "version": "5.7",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "5.7",
                     "status": "unaffected",
                     "versionType": "semver"
                  },
                  {
                     "version": "6.12.11",
                     "lessThanOrEqual": "6.12.*",
                     "status": "unaffected",
                     "versionType": "semver"
                  },
                  {
                     "version": "6.13",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "cpeApplicability": [
            {
               "nodes": [
                  {
                     "operator": "OR",
                     "negate": false,
                     "cpeMatch": [
                        {
                           "vulnerable": true,
                           "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                           "versionStartIncluding": "5.7",
                           "versionEndExcluding": "6.12.11"
                        },
                        {
                           "vulnerable": true,
                           "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                           "versionStartIncluding": "5.7",
                           "versionEndExcluding": "6.13"
                        }
                     ]
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/310ac886d68de661c3a334198d8604b722d7fdf8"
            },
            {
               "url": "https://git.kernel.org/stable/c/0cef0bb836e3cfe00f08f9606c72abd72fe78ca3"
            }
         ],
         "title": "mm: clear uffd-wp PTE/PMD state on mremap()",
         "x_generator": {
            "engine": "bippy-1.2.0"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2025-21696",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}