{"id":"CVE-2026-31589","state":"PUBLISHED","title":"mm: call ->free_folio() directly in folio_unmap_invalidate()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: call ->free_folio() directly in folio_unmap_invalidate()\n\nWe can only call filemap_free_folio() if we have a reference to (or hold a\nlock on) the mapping.  Otherwise, we've already removed the folio from the\nmapping so it no longer pins the mapping and the mapping can be removed,\ncausing a use-after-free when accessing mapping->a_ops.\n\nFollow the same pattern as __remove_mapping() and load the free_folio\nfunction pointer before dropping the lock on the mapping.  That lets us\nmake filemap_free_folio() static as this was the only caller outside\nfilemap.c.","publishedAt":"2026-04-24T14:42:16.955Z","updatedAt":"2026-08-05T12:23:40.286Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"efc52947247a21bbf79059539bbbd40f4ea76f00","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"b667df39d98a7a24be7c2a40ff0863dac1ad2cd7","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"c330e65ea59c4805d6ab6757c4ddfe8c63acef31","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"615d9bb2ccad42f9e21d837431e401db2e471195","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/filemap.c","mm/internal.h","mm/truncate.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.27","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0.1","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/filemap.c","mm/internal.h","mm/truncate.c"]}],"references":["https://git.kernel.org/stable/c/efc52947247a21bbf79059539bbbd40f4ea76f00","https://git.kernel.org/stable/c/b667df39d98a7a24be7c2a40ff0863dac1ad2cd7","https://git.kernel.org/stable/c/c330e65ea59c4805d6ab6757c4ddfe8c63acef31","https://git.kernel.org/stable/c/615d9bb2ccad42f9e21d837431e401db2e471195"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31589.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31589","state":"PUBLISHED","datePublished":"2026-04-24T14:42:16.955Z","dateUpdated":"2026-08-05T12:23:40.286Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.120Z"},"containers":{"cna":{"title":"mm: call ->free_folio() directly in folio_unmap_invalidate()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: call ->free_folio() directly in folio_unmap_invalidate()\n\nWe can only call filemap_free_folio() if we have a reference to (or hold a\nlock on) the mapping.  Otherwise, we've already removed the folio from the\nmapping so it no longer pins the mapping and the mapping can be removed,\ncausing a use-after-free when accessing mapping->a_ops.\n\nFollow the same pattern as __remove_mapping() and load the free_folio\nfunction pointer before dropping the lock on the mapping.  That lets us\nmake filemap_free_folio() static as this was the only caller outside\nfilemap.c."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"efc52947247a21bbf79059539bbbd40f4ea76f00","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"b667df39d98a7a24be7c2a40ff0863dac1ad2cd7","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"c330e65ea59c4805d6ab6757c4ddfe8c63acef31","versionType":"git"},{"version":"fb7d3bc4149395c1ae99029c852eab6c28fc3c88","status":"affected","lessThan":"615d9bb2ccad42f9e21d837431e401db2e471195","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/filemap.c","mm/internal.h","mm/truncate.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.18.27","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.14","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0.1","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/filemap.c","mm/internal.h","mm/truncate.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/efc52947247a21bbf79059539bbbd40f4ea76f00"},{"url":"https://git.kernel.org/stable/c/b667df39d98a7a24be7c2a40ff0863dac1ad2cd7"},{"url":"https://git.kernel.org/stable/c/c330e65ea59c4805d6ab6757c4ddfe8c63acef31"},{"url":"https://git.kernel.org/stable/c/615d9bb2ccad42f9e21d837431e401db2e471195"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable path can be reached by remote NFS clients when nfsd is configured for NFSD_IO_DONTCACHE on a filesystem advertising FOP_DONTCACHE, causing remote READ/WRITE handling to set IOCB_DONTCACHE and enter the dropbehind invalidation path. This is a network-facing kernel service.\nAC:L - Once the affected DONTCACHE path is available, an attacker can repeatedly drive writeback/dropbehind and inode lifetime pressure with ordinary I/O operations. The race is attacker-influenced rather than dependent on an uncontrollable system state.\nPR:N - A remote NFS client can reach nfsd request processing without local shell access or kernel capabilities on the target; permissive or anonymous exports make the relevant file operations reachable without prior target privileges. When uncertain between N and L, N is the higher-severity defensible choice.\nUI:N - No victim user action is needed after the service and export are available. The attacker triggers the path by sending I/O requests.\nS:U - The vulnerability corrupts/uses freed memory inside the same kernel security authority that processes the request. It is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug is a use-after-free of the address_space/inode-backed mapping when dereferencing mapping->a_ops after the folio no longer pins the mapping. Kernel UAFs are defensibly scored as high confidentiality impact because they can be shaped into kernel memory disclosure primitives.\nI:H - The stale mapping dereference includes an indirect free_folio function pointer lookup and potential call, making control-flow or memory corruption exploitation defensible. Kernel UAFs are scored high for integrity under the provided guidance.\nA:H - At minimum, dereferencing mapping->a_ops after the mapping has been freed can crash or oops the kernel. The attacker can trigger the vulnerable path repeatedly, so availability impact is high."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:23:40.286Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18.27"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.19.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.0.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}