CVE-2026-80734

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-80734", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.789Z", "datePublished": "2026-09-03T08:21:50.734Z", "dateUpdated": "2026-10-21T12:47:00.597Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:47:00.597Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: initialize inode mapping flags for cached inodes\n\n[BUG]\nWhen running generic/795 with 8K block size, 4K page size, the test\nalways fails, triggering some ASSERT()s related to folio size:\n\n 795 (241074): drop_caches: 3\n assertion failed: IS_ALIGNED(start, blocksize) && IS_ALIGNED(end + 1, blocksize), in extent_io.c:1404 (blocksize=8192 root=262 ino=258 start=16826368 end=16830463 mapping min order=0)\n ------------[ cut here ]------------\n kernel BUG at extent_io.c:1404!\n Oops: invalid opcode: 0000 [#1] SMP\n CPU: 8 UID: 0 PID: 241105 Comm: fsstress Tainted: G OE 7.2.0-rc5-custom+ #442 PREEMPT(full) f4bfb352566f3949f29c233ce6f735050a03b245\n Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022\n RIP: 0010:assert_folio_range.cold+0x3d/0x3f [btrfs]\n Call Trace:\n <TASK>\n btrfs_read_folio+0x9e/0x170 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n prepare_one_folio.constprop.0+0x104/0x2a0 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n btrfs_buffered_write+0x285/0xa50 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n btrfs_do_write_iter+0x1aa/0x210 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n iter_file_splice_write+0x31a/0x540\n direct_splice_actor+0x53/0x170\n splice_direct_to_actor+0xe9/0x240\n do_splice_direct+0x76/0xb0\n vfs_copy_file_range+0x1fd/0x630\n __x64_sys_copy_file_range+0xf9/0x220\n do_syscall_64+0xe1/0x790\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n </TASK>\n ---[ end trace 0000000000000000 ]---\n\nThe ASSERT() itself is added by a later patch.\nThe crash is triggered with that new debug patch, and without this fix.\n\n[CAUSE]\nIn the above case, the start 16826368 is properly 8K aligned, but the\nend (16830463 + 1) is not 8K aligned.\nFurthermore the mapping's minimal folio order is 0, not the expected 1\nfor 8K block size with 4K page size.\n\nSo this means some inodes do not have btrfs_set_inode_mapping_order()\ncalled on it.\n\nThe missing btrfs_set_inode_mapping_order() call happens for cached\ninodes, through the following events:\n\n- btrfs_create_new_inode() called for inode X\n Which properly sets minimal folio order for the VFS inode.\n\n- btrfs_update_inode() called for inode X\n Which calls btrfs_delayed_update_inode() to create a delayed_node\n into root->delayed_nodes xarray.\n\n- Drop cache/memory pressure, evicting in-memory inode X\n Which evicted the inode X, but delayed_node is still in\n root->delayed_nodes for future reuse.\n\n- btrfs_iget() for inode X called again\n\n btrfs_iget()\n |- btrfs_iget_locked()\n | |- iget5_locked_rcu()\n | Which creates a new vfs_inode for btrfs, whose mapping still\n | has the minimal order as 0.\n |\n |- btrfs_read_locked_inode()\n |- btrfs_fill_inode()\n | |- btrfs_get_delayed_node()\n | Which found out the previous node, and use that delayed\n | node to initialize the new inode.\n |\n |- filled = true;\n |- if (filled) goto cache_index;\n Which skips the btrfs_update_inode_mapping_flags() and\n\tbtrfs_set_inode_mapping_order() calls.\n\tSo the inode still has minimal folio order set as 0, not\n\tthe required 1.\n\nThus later page cache read will get a folio whose size is smaller than\nblock size, as the mapping has its minimal folio order set as 0 not 1,\nthen trigger the ASSERT().\n\n[FIX]\nMove the btrfs_update_inode_mapping_flags() and\nbtrfs_set_inode_mapping_order() calls under cache_index label,\nso that the mapping flags and minimal folio order is always set\nno matter if we have a cached inode."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - The fault is reached from vfs_copy_file_range/splice buffered-write paths on btrfs inodes (as in the xfstest repro); on NFS-exported btrfs volumes remote clients can drive the same VFS copy_file_range path via nfsd NFSv4 COPY, making this network-reachable on NAS deployments.\nAC:L - Once a btrfs volume uses CONFIG_BTRFS_EXPERIMENTAL blocksize>pagesize, an attacker can deterministically create the delayed-node/evict/re-iget sequence with ordinary writes plus memory pressure (xfstest generic/795 reproduces reliably) without uncontrollable races or layout luck.\nPR:L - Triggering requires only write access to files on a mounted btrfs filesystem (or an authenticated NFS/SMB client with export write permission); no init-namespace root or non-namespace capabilities are needed beyond normal filesystem access.\nUI:N - No victim interaction is required; the attacker issues their own copy_file_range/write/splice syscalls (or remote COPY) after creating the inode state, without needing another user to mount, open, or click anything.\nS:U - Impact is confined to incorrect btrfs page-cache I/O and filesystem data/kernel stability on the host; it does not cross VM, container, IOMMU, or other security-authority boundaries.\nC:H - Skipping btrfs_set_inode_mapping_order leaves 4K folios on 8K-sector volumes, so read paths operate on block-misaligned ranges and can return stale adjacent on-disk sectors into attacker buffers, disclosing other users' btrfs file content on shared volumes.\nI:H - Wrong mapping min folio order and stable-writes flags break btrfs block-aligned buffered I/O invariants, allowing misaligned writes/checksum-unsafe writeback that can persist corrupted data and violate CoW/checksum integrity on the affected volume.\nA:H - The bug provokes kernel BUG/oops via assert_folio_range on misaligned folio ranges (documented in the fix commit), and blocks_per_folio becomes zero when folio_size<sectorsize, breaking subpage bitmap assumptions and risking further kernel faults or wedged I/O."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/btrfs/inode.c"], "versions": [{"version": "01b002151539a4c2b27bfff9af033329a9b659e7", "lessThan": "e4d997a1ec1d0dbb72dde35a99fda1850fee6a53", "status": "affected", "versionType": "git"}, {"version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "lessThan": "e18b8236c57fcc67d793bfc866f4bb2581be9f72", "status": "affected", "versionType": "git"}, {"version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "lessThan": "0d26249671171ab759cb4fdce673554a690fa655", "status": "affected", "versionType": "git"}, {"version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "lessThan": "0ef349734a93227b45f65fc50a3311d1cc5f03e9", "status": "affected", "versionType": "git"}, {"version": "ae584726e6eddf6cfbe49b3f4a78b3197716b6f8", "status": "affected", "versionType": "git"}, {"version": "6.12.111", "lessThan": "6.12.114", "status": "affected", "versionType": "semver"}, {"version": "6.14.6", "lessThan": "6.15", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/btrfs/inode.c"], "versions": [{"version": "6.15", "status": "affected"}, {"version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.56", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2", "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": "6.12.111", "versionEndExcluding": "6.12.114"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.56"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14.6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/e4d997a1ec1d0dbb72dde35a99fda1850fee6a53"}, {"url": "https://git.kernel.org/stable/c/e18b8236c57fcc67d793bfc866f4bb2581be9f72"}, {"url": "https://git.kernel.org/stable/c/0d26249671171ab759cb4fdce673554a690fa655"}, {"url": "https://git.kernel.org/stable/c/0ef349734a93227b45f65fc50a3311d1cc5f03e9"}], "title": "btrfs: initialize inode mapping flags for cached inodes", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/btrfs/inode.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "e4d997a1ec1d0dbb72dde35a99fda1850fee6a53", "status": "affected", "version": "01b002151539a4c2b27bfff9af033329a9b659e7", "versionType": "git"}, {"lessThan": "e18b8236c57fcc67d793bfc866f4bb2581be9f72", "status": "affected", "version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "versionType": "git"}, {"lessThan": "0d26249671171ab759cb4fdce673554a690fa655", "status": "affected", "version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "versionType": "git"}, {"lessThan": "0ef349734a93227b45f65fc50a3311d1cc5f03e9", "status": "affected", "version": "ecde48a1a6b3256bd49db8780bf37556b157783c", "versionType": "git"}, {"status": "affected", "version": "ae584726e6eddf6cfbe49b3f4a78b3197716b6f8", "versionType": "git"}, {"lessThan": "6.12.114", "status": "affected", "version": "6.12.111", "versionType": "semver"}, {"lessThan": "6.15", "status": "affected", "version": "6.14.6", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/btrfs/inode.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.15"}, {"lessThan": "6.15", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.114", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.56", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: initialize inode mapping flags for cached inodes\n\n[BUG]\nWhen running generic/795 with 8K block size, 4K page size, the test\nalways fails, triggering some ASSERT()s related to folio size:\n\n 795 (241074): drop_caches: 3\n assertion failed: IS_ALIGNED(start, blocksize) && IS_ALIGNED(end + 1, blocksize), in extent_io.c:1404 (blocksize=8192 root=262 ino=258 start=16826368 end=16830463 mapping min order=0)\n ------------[ cut here ]------------\n kernel BUG at extent_io.c:1404!\n Oops: invalid opcode: 0000 [#1] SMP\n CPU: 8 UID: 0 PID: 241105 Comm: fsstress Tainted: G OE 7.2.0-rc5-custom+ #442 PREEMPT(full) f4bfb352566f3949f29c233ce6f735050a03b245\n Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022\n RIP: 0010:assert_folio_range.cold+0x3d/0x3f [btrfs]\n Call Trace:\n <TASK>\n btrfs_read_folio+0x9e/0x170 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n prepare_one_folio.constprop.0+0x104/0x2a0 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n btrfs_buffered_write+0x285/0xa50 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n btrfs_do_write_iter+0x1aa/0x210 [btrfs 4cd1dd93b341b8ef766643f9512f4a86259567a3]\n iter_file_splice_write+0x31a/0x540\n direct_splice_actor+0x53/0x170\n splice_direct_to_actor+0xe9/0x240\n do_splice_direct+0x76/0xb0\n vfs_copy_file_range+0x1fd/0x630\n __x64_sys_copy_file_range+0xf9/0x220\n do_syscall_64+0xe1/0x790\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n </TASK>\n ---[ end trace 0000000000000000 ]---\n\nThe ASSERT() itself is added by a later patch.\nThe crash is triggered with that new debug patch, and without this fix.\n\n[CAUSE]\nIn the above case, the start 16826368 is properly 8K aligned, but the\nend (16830463 + 1) is not 8K aligned.\nFurthermore the mapping's minimal folio order is 0, not the expected 1\nfor 8K block size with 4K page size.\n\nSo this means some inodes do not have btrfs_set_inode_mapping_order()\ncalled on it.\n\nThe missing btrfs_set_inode_mapping_order() call happens for cached\ninodes, through the following events:\n\n- btrfs_create_new_inode() called for inode X\n Which properly sets minimal folio order for the VFS inode.\n\n- btrfs_update_inode() called for inode X\n Which calls btrfs_delayed_update_inode() to create a delayed_node\n into root->delayed_nodes xarray.\n\n- Drop cache/memory pressure, evicting in-memory inode X\n Which evicted the inode X, but delayed_node is still in\n root->delayed_nodes for future reuse.\n\n- btrfs_iget() for inode X called again\n\n btrfs_iget()\n |- btrfs_iget_locked()\n | |- iget5_locked_rcu()\n | Which creates a new vfs_inode for btrfs, whose mapping still\n | has the minimal order as 0.\n |\n |- btrfs_read_locked_inode()\n |- btrfs_fill_inode()\n | |- btrfs_get_delayed_node()\n | Which found out the previous node, and use that delayed\n | node to initialize the new inode.\n |\n |- filled = true;\n |- if (filled) goto cache_index;\n Which skips the btrfs_update_inode_mapping_flags() and\n\tbtrfs_set_inode_mapping_order() calls.\n\tSo the inode still has minimal folio order set as 0, not\n\tthe required 1.\n\nThus later page cache read will get a folio whose size is smaller than\nblock size, as the mapping has its minimal folio order set as 0 not 1,\nthen trigger the ASSERT().\n\n[FIX]\nMove the btrfs_update_inode_mapping_flags() and\nbtrfs_set_inode_mapping_order() calls under cache_index label,\nso that the mapping flags and minimal folio order is always set\nno matter if we have a cached inode."}], "id": "CVE-2026-80734", "lastModified": "2026-10-21T13:19:59.257", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-03T13:06:12.200", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0d26249671171ab759cb4fdce673554a690fa655"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0ef349734a93227b45f65fc50a3311d1cc5f03e9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e18b8236c57fcc67d793bfc866f4bb2581be9f72"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e4d997a1ec1d0dbb72dde35a99fda1850fee6a53"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ecde48a1a6b3256bd49db8780bf37556b157783c,0d26249671171ab759cb4fdce673554a690fa655)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[ecde48a1a6b3256bd49db8780bf37556b157783c,0ef349734a93227b45f65fc50a3311d1cc5f03e9)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "ae584726e6eddf6cfbe49b3f4a78b3197716b6f8"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.14.6,6.15)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.15"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.15)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.9,7.2.0]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-03T12:30:03.812104+00:00", "updated": "2026-09-04T10:00:05.065494+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-665"]}