CVE-2026-98986
UnknownSummary
In the Linux kernel, mnt_ns_release() removes fanotify marks of a mount namespace in process context, but mnt_ns_tree_remove() hands the reference to call_rcu(), so marks are removed from RCU softirq. This triggers a "sleeping function called from invalid context" BUG and lockdep warnings about the connector lock. A fanotify group with a FAN_MARK_MNTNS mark on another task's mount namespace is sufficient.
Risk Assessment
A local user with user namespace privileges can trigger a kernel BUG, causing a denial of service (panic or hang). This is a local denial-of-service vector.
Recommendation
Update the Linux kernel to a version containing the fix. Consider restricting unprivileged user namespace creation and mounts.
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- CVE-2026-58828High
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- CVE-2026-58826High
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- CVE-2026-99242Unknown
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- CVE-2026-99241Unknown
In the Linux kernel, a missing lock in ntfs_filemap_page_mkwrite() was fixed; it called iomap_page_mkwrite() without holding mapping->invalidate_lock. A concurrent truncate or fallocate could be invalidating pagecache and rewriting the runlist while the write fault mapped blocks and dirtied the folio.
- CVE-2026-99240Unknown
In the Linux kernel, the DAMON subsystem (mm/damon/core) has a division-by-zero bug when a DAMOS quota goal has a target_value of zero. The fix moves handling of this corner case to the core layer by adding validation in damos_commit_quota_goal(), which now returns an error for zero target values.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: namespace: remove the fsnotify marks of a mount namespace in process context mnt_ns_release() drops the last passive reference of a mount namespace and removes its fanotify marks via fsnotify_mntns_delete(). That takes the mutex of every group with a mark on the namespace and the spinlock of the connector. Fine from process context. But mnt_ns_tree_remove() hands the reference the namespace was allocated with to call_rcu() and so the marks are removed from the RCU softirq: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:623 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/3 __mutex_lock+0x113/0x24b0 fsnotify_destroy_marks+0x11b/0x3d0 mnt_ns_release_rcu+0x57/0xa0 rcu_core+0x6b6/0x1e40 and lockdep complains about the connector lock being taken from softirq context. A fanotify group with a FAN_MARK_MNTNS mark on the mount namespace of another task is all that's needed. Root in a user namespace can do that for a mount namespace it owns. The task exits and the namespace is freed with the mark still on it. Remove the marks in free_mnt_ns() before the namespace is handed to RCU. That runs in process context once the last active reference is gone. A mark is added through a file descriptor to the namespace which holds an active reference so no mark can show up after that.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS