{"api_version":"1","generated_at":"2026-05-12T15:57:04+00:00","cve":"CVE-2026-43389","urls":{"html":"https://cve.report/CVE-2026-43389","api":"https://cve.report/api/cve/CVE-2026-43389.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43389","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43389"},"summary":{"title":"mm: memfd_luo: always dirty all folios","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: memfd_luo: always dirty all folios\n\nA dirty folio is one which has been written to.  A clean folio is its\nopposite.  Since a clean folio has no user data, it can be freed under\nmemory pressure.\n\nmemfd preservation with LUO saves the flag at preserve().  This is\nproblematic.  The folio might get dirtied later.  Saving it at freeze()\nalso doesn't work, since the dirty bit from PTE is normally synced at\nunmap and there might still be mappings of the file at freeze().\n\nTo see why this is a problem, say a folio is clean at preserve, but gets\ndirtied later.  The serialized state of the folio will mark it as clean. \nAfter retrieve, the next kernel will see the folio as clean and might try\nto reclaim it under memory pressure.  This will result in losing user\ndata.\n\nMark all folios of the file as dirty, and always set the\nMEMFD_LUO_FOLIO_DIRTY flag.  This comes with the side effect of making all\nclean folios un-reclaimable.  This is a cost that has to be paid for\nparticipants of live update.  It is not expected to be a common use case\nto preserve a lot of clean folios anyway.\n\nSince the value of pfolio->flags is a constant now, drop the flags\nvariable and set it directly.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-08 15:16:50","updated_at":"2026-05-12 14:10:27"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/7e04bf1f33151a30e06a65b74b5f2c19fc2be128","name":"https://git.kernel.org/stable/c/7e04bf1f33151a30e06a65b74b5f2c19fc2be128","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e901c871d4b592f0042e30f3a0f031eae79744ec","name":"https://git.kernel.org/stable/c/e901c871d4b592f0042e30f3a0f031eae79744ec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43389","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43389","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3749f174d686627f702234e64bad976dc432dbc e901c871d4b592f0042e30f3a0f031eae79744ec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b3749f174d686627f702234e64bad976dc432dbc 7e04bf1f33151a30e06a65b74b5f2c19fc2be128 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.19","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.9 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"43389","cve":"CVE-2026-43389","epss":"0.000180000","percentile":"0.050780000","score_date":"2026-05-11","updated_at":"2026-05-12 00:01:18"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/memfd_luo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e901c871d4b592f0042e30f3a0f031eae79744ec","status":"affected","version":"b3749f174d686627f702234e64bad976dc432dbc","versionType":"git"},{"lessThan":"7e04bf1f33151a30e06a65b74b5f2c19fc2be128","status":"affected","version":"b3749f174d686627f702234e64bad976dc432dbc","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/memfd_luo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.19"},{"lessThan":"6.19","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.9","versionStartIncluding":"6.19","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"6.19","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: memfd_luo: always dirty all folios\n\nA dirty folio is one which has been written to.  A clean folio is its\nopposite.  Since a clean folio has no user data, it can be freed under\nmemory pressure.\n\nmemfd preservation with LUO saves the flag at preserve().  This is\nproblematic.  The folio might get dirtied later.  Saving it at freeze()\nalso doesn't work, since the dirty bit from PTE is normally synced at\nunmap and there might still be mappings of the file at freeze().\n\nTo see why this is a problem, say a folio is clean at preserve, but gets\ndirtied later.  The serialized state of the folio will mark it as clean. \nAfter retrieve, the next kernel will see the folio as clean and might try\nto reclaim it under memory pressure.  This will result in losing user\ndata.\n\nMark all folios of the file as dirty, and always set the\nMEMFD_LUO_FOLIO_DIRTY flag.  This comes with the side effect of making all\nclean folios un-reclaimable.  This is a cost that has to be paid for\nparticipants of live update.  It is not expected to be a common use case\nto preserve a lot of clean folios anyway.\n\nSince the value of pfolio->flags is a constant now, drop the flags\nvariable and set it directly."}],"providerMetadata":{"dateUpdated":"2026-05-11T22:23:38.437Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e901c871d4b592f0042e30f3a0f031eae79744ec"},{"url":"https://git.kernel.org/stable/c/7e04bf1f33151a30e06a65b74b5f2c19fc2be128"}],"title":"mm: memfd_luo: always dirty all folios","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43389","datePublished":"2026-05-08T14:21:34.658Z","dateReserved":"2026-05-01T14:12:56.007Z","dateUpdated":"2026-05-11T22:23:38.437Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-08 15:16:50","lastModifiedDate":"2026-05-12 14:10:27","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43389","Ordinal":"1","Title":"mm: memfd_luo: always dirty all folios","CVE":"CVE-2026-43389","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43389","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: memfd_luo: always dirty all folios\n\nA dirty folio is one which has been written to.  A clean folio is its\nopposite.  Since a clean folio has no user data, it can be freed under\nmemory pressure.\n\nmemfd preservation with LUO saves the flag at preserve().  This is\nproblematic.  The folio might get dirtied later.  Saving it at freeze()\nalso doesn't work, since the dirty bit from PTE is normally synced at\nunmap and there might still be mappings of the file at freeze().\n\nTo see why this is a problem, say a folio is clean at preserve, but gets\ndirtied later.  The serialized state of the folio will mark it as clean. \nAfter retrieve, the next kernel will see the folio as clean and might try\nto reclaim it under memory pressure.  This will result in losing user\ndata.\n\nMark all folios of the file as dirty, and always set the\nMEMFD_LUO_FOLIO_DIRTY flag.  This comes with the side effect of making all\nclean folios un-reclaimable.  This is a cost that has to be paid for\nparticipants of live update.  It is not expected to be a common use case\nto preserve a lot of clean folios anyway.\n\nSince the value of pfolio->flags is a constant now, drop the flags\nvariable and set it directly.","Type":"Description","Title":"mm: memfd_luo: always dirty all folios"}]}}}