CVE-2026-64359
nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers
Description
In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers Syzbot reported a hung task in nilfs_transaction_begin() where multiple tasks performing chmod() on a nilfs2 mount blocked for over 143 seconds waiting to acquire ns_segctor_sem for read: INFO: task syz.0.17:5918 blocked for more than 143 seconds. Call Trace: schedule+0x164/0x360 rwsem_down_read_slowpath+0x6d9/0x940 down_read+0x99/0x2e0 nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221 nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921 notify_change+0xc1a/0xf40 chmod_common+0x273/0x4a0 do_fchmodat+0x12d/0x230 The writer holding ns_segctor_sem was a concurrent NILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting per-element warnings from nilfs_sufile_updatev(): __nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78 nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186 nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline] nilfs_free_segments fs/nilfs2/segment.c:1140 [inline] nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline] nilfs_segctor_do_construct+0x1f55/0x76c0 nilfs_clean_segments+0x3bd/0xa50 nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline] nilfs_ioctl+0x261f/0x2780 The root cause is that user-supplied segment numbers are not validated before nilfs_clean_segments() begins doing work; the range check on each segnum is performed deep inside the call chain by nilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry while still holding the segctor lock and the sufile mi_sem. Under load (repeated invocations across multiple mounts saturating the global printk path), the cumulative printk latency keeps ns_segctor_sem held long enough to trip the hung_task watchdog, blocking concurrent operations such as chmod() that need ns_segctor_sem for read. Fix by validating the contents of kbufs[4] in nilfs_clean_segments() immediately after acquiring ns_segctor_sem via nilfs_transaction_lock(). Holding ns_segctor_sem serializes the check against nilfs_ioctl_resize(), which can modify ns_nsegments, so the validation uses a consistent value. Out-of-range segment numbers are rejected with -EINVAL before any segment-cleaning work begins, so the bad entries never reach the per-element diagnostic path inside nilfs_sufile_updatev().
INFO
Published Date :
July 25, 2026, 10:17 a.m.
Last Modified :
Aug. 17, 2026, 5:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Validate segment numbers in nilfs_clean_segments immediately.
- Reject out-of-range segment numbers with -EINVAL.
- Ensure checks use a consistent value for ns_nsegments.
- Update the Linux kernel to the patched version.
References to Advisories, Solutions, and Tools
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information, practical solutions, and valuable tools related to
CVE-2026-64359.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64359 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64359
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64359 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64359 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '876c98e0fc65f071680c03c2e2ee3ef7ff9ca078', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '39607452b1400c7bf748f15122df4d058b768c5b', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '286f77d002a337735c0846d7480a82d9cda2aa31', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '223463c488b0554212a94de971ea538eb2805fc7', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': 'd26aef771b4f6923da9f89d6d5b70d8def5853de', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9', 'versionType': 'git'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.31'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.31', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '876c98e0fc65f071680c03c2e2ee3ef7ff9ca078', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '39607452b1400c7bf748f15122df4d058b768c5b', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '286f77d002a337735c0846d7480a82d9cda2aa31', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '223463c488b0554212a94de971ea538eb2805fc7', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': 'd26aef771b4f6923da9f89d6d5b70d8def5853de', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9', 'versionType': 'git'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.31'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.31', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '876c98e0fc65f071680c03c2e2ee3ef7ff9ca078', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '39607452b1400c7bf748f15122df4d058b768c5b', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '286f77d002a337735c0846d7480a82d9cda2aa31', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '223463c488b0554212a94de971ea538eb2805fc7', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': 'd26aef771b4f6923da9f89d6d5b70d8def5853de', 'versionType': 'git'}, {'status': 'affected', 'version': '071cb4b81987a28c7ac2702003cff3e61684a630', 'lessThan': '0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9', 'versionType': 'git'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '2.6.31'}, {'status': 'unaffected', 'version': '0', 'lessThan': '2.6.31', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/nilfs2/segment.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject CLEAN_SEGMENTS ioctl with out-of-range segment numbers Syzbot reported a hung task in nilfs_transaction_begin() where multiple tasks performing chmod() on a nilfs2 mount blocked for over 143 seconds waiting to acquire ns_segctor_sem for read: INFO: task syz.0.17:5918 blocked for more than 143 seconds. Call Trace: schedule+0x164/0x360 rwsem_down_read_slowpath+0x6d9/0x940 down_read+0x99/0x2e0 nilfs_transaction_begin+0x364/0x710 fs/nilfs2/segment.c:221 nilfs_setattr+0x124/0x2c0 fs/nilfs2/inode.c:921 notify_change+0xc1a/0xf40 chmod_common+0x273/0x4a0 do_fchmodat+0x12d/0x230 The writer holding ns_segctor_sem was a concurrent NILFS_IOCTL_CLEAN_SEGMENTS caller, stuck inside printk while emitting per-element warnings from nilfs_sufile_updatev(): __nilfs_msg+0x373/0x450 fs/nilfs2/super.c:78 nilfs_sufile_updatev+0x21c/0x6d0 fs/nilfs2/sufile.c:186 nilfs_sufile_freev fs/nilfs2/sufile.h:93 [inline] nilfs_free_segments fs/nilfs2/segment.c:1140 [inline] nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1261 [inline] nilfs_segctor_do_construct+0x1f55/0x76c0 nilfs_clean_segments+0x3bd/0xa50 nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:922 [inline] nilfs_ioctl+0x261f/0x2780 The root cause is that user-supplied segment numbers are not validated before nilfs_clean_segments() begins doing work; the range check on each segnum is performed deep inside the call chain by nilfs_sufile_updatev(), which emits a nilfs_warn() per invalid entry while still holding the segctor lock and the sufile mi_sem. Under load (repeated invocations across multiple mounts saturating the global printk path), the cumulative printk latency keeps ns_segctor_sem held long enough to trip the hung_task watchdog, blocking concurrent operations such as chmod() that need ns_segctor_sem for read. Fix by validating the contents of kbufs[4] in nilfs_clean_segments() immediately after acquiring ns_segctor_sem via nilfs_transaction_lock(). Holding ns_segctor_sem serializes the check against nilfs_ioctl_resize(), which can modify ns_nsegments, so the validation uses a consistent value. Out-of-range segment numbers are rejected with -EINVAL before any segment-cleaning work begins, so the bad entries never reach the per-element diagnostic path inside nilfs_sufile_updatev(). Added Reference https://git.kernel.org/stable/c/0789f0a6710713254a08f3a7d2ecbb6d1cbcf0aa Added Reference https://git.kernel.org/stable/c/0e7a690fe435f8d5ea3feb7c1d8d73ba7e8b8aa9 Added Reference https://git.kernel.org/stable/c/223463c488b0554212a94de971ea538eb2805fc7 Added Reference https://git.kernel.org/stable/c/286f77d002a337735c0846d7480a82d9cda2aa31 Added Reference https://git.kernel.org/stable/c/39607452b1400c7bf748f15122df4d058b768c5b Added Reference https://git.kernel.org/stable/c/3ed388ec3b8922383d1e2d4432d7bd4cbbf8364e Added Reference https://git.kernel.org/stable/c/876c98e0fc65f071680c03c2e2ee3ef7ff9ca078 Added Reference https://git.kernel.org/stable/c/d26aef771b4f6923da9f89d6d5b70d8def5853de