Answer in brief
CVE-2026-98986 records a Unknown severity vulnerability in namespace: remove the fsnotify marks of a mount namespace in process context. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=bf630c40164162ba1d3933c2f5e3397d083e0948 <888363d74c3b5d32e2accf217add70f8b38e0e2b || >=bf630c40164162ba1d3933c2f5e3397d083e0948 <9e820a6becdd955a04adbedfd767253a47eedd9e || >=bf630c40164162ba1d3933c2f5e3397d083e0948 <1a116222acdcc1bc1a8350727ae6f28907d44594 | 888363d74c3b5d32e2accf217add70f8b38e0e2b, 9e820a6becdd955a04adbedfd767253a47eedd9e, 1a116222acdcc1bc1a8350727ae6f28907d44594 |
| Linux/Linuxgeneric | 6.15 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
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.
Quoted source text, attributed separately from HOL analysis.