{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64359", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.782Z", "datePublished": "2026-07-25T08:50:15.947Z", "dateUpdated": "2026-08-17T04:54:05.599Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:54:05.599Z" }, "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()." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nilfs2/segment.c" ], "versions": [ { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "876c98e0fc65f071680c03c2e2ee3ef7ff9ca078", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "39607452b1400c7bf748f15122df4d058b768c5b", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "286f77d002a337735c0846d7480a82d9cda2aa31", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "223463c488b0554212a94de971ea538eb2805fc7", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "d26aef771b4f6923da9f89d6d5b70d8def5853de", "status": "affected", "versionType": "git" }, { "version": "071cb4b81987a28c7ac2702003cff3e61684a630", "lessThan": "0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/nilfs2/segment.c" ], "versions": [ { "version": "2.6.31", "status": "affected" }, { "version": "0", "lessThan": "2.6.31", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "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": "2.6.31", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }