{"api_version":"1","generated_at":"2026-08-09T11:30:30+00:00","cve":"CVE-2026-64359","urls":{"html":"https://cve.report/CVE-2026-64359","api":"https://cve.report/api/cve/CVE-2026-64359.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64359","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64359"},"summary":{"title":"nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers\n\nSyzbot reported a hung task in nilfs_transaction_begin() where multiple\ntasks performing chmod() on a nilfs2 mount blocked for over 143 seconds\nwaiting to acquire ns_segctor_sem for read:\n\n  INFO: task syz.0.17:5918 blocked for more than 143 seconds.\n  Call Trace:\n   schedule+0x164/0x360\n   rwsem_down_read_slowpath+0x6d9/0x940\n   down_read+0x99/0x2e0\n   nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221\n   nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921\n   notify_change+0xc1a/0xf40\n   chmod_common+0x273/0x4a0\n   do_fchmodat+0x12d/0x230\n\nThe writer holding ns_segctor_sem was a concurrent\nNILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting\nper-element warnings from nilfs_sufile_updatev():\n\n   __nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78\n   nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186\n   nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline]\n   nilfs_free_segments fs/nilfs2/segment.c:1140 [inline]\n   nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline]\n   nilfs_segctor_do_construct+0x1f55/0x76c0\n   nilfs_clean_segments+0x3bd/0xa50\n   nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline]\n   nilfs_ioctl+0x261f/0x2780\n\nThe root cause is that user-supplied segment numbers are not validated\nbefore nilfs_clean_segments() begins doing work; the range check on\neach segnum is performed deep inside the call chain by\nnilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry\nwhile still holding the segctor lock and the sufile mi_sem.  Under load\n(repeated invocations across multiple mounts saturating the global\nprintk path), the cumulative printk latency keeps ns_segctor_sem held\nlong enough to trip the hung_task watchdog, blocking concurrent\noperations such as chmod() that need ns_segctor_sem for read.\n\nFix by validating the contents of kbufs[4] in nilfs_clean_segments()\nimmediately after acquiring ns_segctor_sem via nilfs_transaction_lock().\nHolding ns_segctor_sem serializes the check against\nnilfs_ioctl_resize(), which can modify ns_nsegments, so the validation\nuses a consistent value.  Out-of-range segment numbers are rejected\nwith -EINVAL before any segment-cleaning work begins, so the bad\nentries never reach the per-element diagnostic path inside\nnilfs_sufile_updatev().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:18","updated_at":"2026-07-25 10:17:18"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e","name":"https://git.kernel.org/stable/c/3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9","name":"https://git.kernel.org/stable/c/0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/286f77d002a337735c0846d7480a82d9cda2aa31","name":"https://git.kernel.org/stable/c/286f77d002a337735c0846d7480a82d9cda2aa31","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/39607452b1400c7bf748f15122df4d058b768c5b","name":"https://git.kernel.org/stable/c/39607452b1400c7bf748f15122df4d058b768c5b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/223463c488b0554212a94de971ea538eb2805fc7","name":"https://git.kernel.org/stable/c/223463c488b0554212a94de971ea538eb2805fc7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d26aef771b4f6923da9f89d6d5b70d8def5853de","name":"https://git.kernel.org/stable/c/d26aef771b4f6923da9f89d6d5b70d8def5853de","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa","name":"https://git.kernel.org/stable/c/0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/876c98e0fc65f071680c03c2e2ee3ef7ff9ca078","name":"https://git.kernel.org/stable/c/876c98e0fc65f071680c03c2e2ee3ef7ff9ca078","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64359","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64359","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 876c98e0fc65f071680c03c2e2ee3ef7ff9ca078 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 39607452b1400c7bf748f15122df4d058b768c5b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 286f77d002a337735c0846d7480a82d9cda2aa31 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 223463c488b0554212a94de971ea538eb2805fc7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 d26aef771b4f6923da9f89d6d5b70d8def5853de git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 071cb4b81987a28c7ac2702003cff3e61684a630 0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 2.6.31","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 2.6.31 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.261 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64359","cve":"CVE-2026-64359","epss":"0.001770000","percentile":"0.075080000","score_date":"2026-07-28","updated_at":"2026-07-29 00:05:33"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/nilfs2/segment.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"876c98e0fc65f071680c03c2e2ee3ef7ff9ca078","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"39607452b1400c7bf748f15122df4d058b768c5b","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"286f77d002a337735c0846d7480a82d9cda2aa31","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"223463c488b0554212a94de971ea538eb2805fc7","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"d26aef771b4f6923da9f89d6d5b70d8def5853de","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"},{"lessThan":"0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9","status":"affected","version":"071cb4b81987a28c7ac2702003cff3e61684a630","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/nilfs2/segment.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"2.6.31"},{"lessThan":"2.6.31","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.261","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.212","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.261","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.212","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"2.6.31","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"2.6.31","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers\n\nSyzbot reported a hung task in nilfs_transaction_begin() where multiple\ntasks performing chmod() on a nilfs2 mount blocked for over 143 seconds\nwaiting to acquire ns_segctor_sem for read:\n\n  INFO: task syz.0.17:5918 blocked for more than 143 seconds.\n  Call Trace:\n   schedule+0x164/0x360\n   rwsem_down_read_slowpath+0x6d9/0x940\n   down_read+0x99/0x2e0\n   nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221\n   nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921\n   notify_change+0xc1a/0xf40\n   chmod_common+0x273/0x4a0\n   do_fchmodat+0x12d/0x230\n\nThe writer holding ns_segctor_sem was a concurrent\nNILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting\nper-element warnings from nilfs_sufile_updatev():\n\n   __nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78\n   nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186\n   nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline]\n   nilfs_free_segments fs/nilfs2/segment.c:1140 [inline]\n   nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline]\n   nilfs_segctor_do_construct+0x1f55/0x76c0\n   nilfs_clean_segments+0x3bd/0xa50\n   nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline]\n   nilfs_ioctl+0x261f/0x2780\n\nThe root cause is that user-supplied segment numbers are not validated\nbefore nilfs_clean_segments() begins doing work; the range check on\neach segnum is performed deep inside the call chain by\nnilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry\nwhile still holding the segctor lock and the sufile mi_sem.  Under load\n(repeated invocations across multiple mounts saturating the global\nprintk path), the cumulative printk latency keeps ns_segctor_sem held\nlong enough to trip the hung_task watchdog, blocking concurrent\noperations such as chmod() that need ns_segctor_sem for read.\n\nFix by validating the contents of kbufs[4] in nilfs_clean_segments()\nimmediately after acquiring ns_segctor_sem via nilfs_transaction_lock().\nHolding ns_segctor_sem serializes the check against\nnilfs_ioctl_resize(), which can modify ns_nsegments, so the validation\nuses a consistent value.  Out-of-range segment numbers are rejected\nwith -EINVAL before any segment-cleaning work begins, so the bad\nentries never reach the per-element diagnostic path inside\nnilfs_sufile_updatev()."}],"providerMetadata":{"dateUpdated":"2026-07-25T08:50:15.947Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e"},{"url":"https://git.kernel.org/stable/c/876c98e0fc65f071680c03c2e2ee3ef7ff9ca078"},{"url":"https://git.kernel.org/stable/c/39607452b1400c7bf748f15122df4d058b768c5b"},{"url":"https://git.kernel.org/stable/c/286f77d002a337735c0846d7480a82d9cda2aa31"},{"url":"https://git.kernel.org/stable/c/0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa"},{"url":"https://git.kernel.org/stable/c/223463c488b0554212a94de971ea538eb2805fc7"},{"url":"https://git.kernel.org/stable/c/d26aef771b4f6923da9f89d6d5b70d8def5853de"},{"url":"https://git.kernel.org/stable/c/0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9"}],"title":"nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64359","datePublished":"2026-07-25T08:50:15.947Z","dateReserved":"2026-07-19T15:36:31.782Z","dateUpdated":"2026-07-25T08:50:15.947Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:18","lastModifiedDate":"2026-07-25 10:17:18","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64359","Ordinal":"1","Title":"nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment nu","CVE":"CVE-2026-64359","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64359","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers\n\nSyzbot reported a hung task in nilfs_transaction_begin() where multiple\ntasks performing chmod() on a nilfs2 mount blocked for over 143 seconds\nwaiting to acquire ns_segctor_sem for read:\n\n  INFO: task syz.0.17:5918 blocked for more than 143 seconds.\n  Call Trace:\n   schedule+0x164/0x360\n   rwsem_down_read_slowpath+0x6d9/0x940\n   down_read+0x99/0x2e0\n   nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221\n   nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921\n   notify_change+0xc1a/0xf40\n   chmod_common+0x273/0x4a0\n   do_fchmodat+0x12d/0x230\n\nThe writer holding ns_segctor_sem was a concurrent\nNILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting\nper-element warnings from nilfs_sufile_updatev():\n\n   __nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78\n   nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186\n   nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline]\n   nilfs_free_segments fs/nilfs2/segment.c:1140 [inline]\n   nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline]\n   nilfs_segctor_do_construct+0x1f55/0x76c0\n   nilfs_clean_segments+0x3bd/0xa50\n   nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline]\n   nilfs_ioctl+0x261f/0x2780\n\nThe root cause is that user-supplied segment numbers are not validated\nbefore nilfs_clean_segments() begins doing work; the range check on\neach segnum is performed deep inside the call chain by\nnilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry\nwhile still holding the segctor lock and the sufile mi_sem.  Under load\n(repeated invocations across multiple mounts saturating the global\nprintk path), the cumulative printk latency keeps ns_segctor_sem held\nlong enough to trip the hung_task watchdog, blocking concurrent\noperations such as chmod() that need ns_segctor_sem for read.\n\nFix by validating the contents of kbufs[4] in nilfs_clean_segments()\nimmediately after acquiring ns_segctor_sem via nilfs_transaction_lock().\nHolding ns_segctor_sem serializes the check against\nnilfs_ioctl_resize(), which can modify ns_nsegments, so the validation\nuses a consistent value.  Out-of-range segment numbers are rejected\nwith -EINVAL before any segment-cleaning work begins, so the bad\nentries never reach the per-element diagnostic path inside\nnilfs_sufile_updatev().","Type":"Description","Title":"nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment nu"}]}}}