Unknown

CVE-2026-98986 — namespace: remove the fsnotify marks of a mount namespace in process context

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.

Published Oct 23, 2026 · Updated Oct 23, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.17%

ahead of 7% of scored CVEs · Oct 30, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ bf630c40164162ba1d3933c2f5e3397d083e0948 and < 888363d74c3b5d32e2accf217add70f8b38e0e2b≥ bf630c40164162ba1d3933c2f5e3397d083e0948 and < 9e820a6becdd955a04adbedfd767253a47eedd9e≥ bf630c40164162ba1d3933c2f5e3397d083e0948 and < 1a116222acdcc1bc1a8350727ae6f28907d44594version 6.15	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 24, 2026 → Oct 30, 2026 · 7 reading(s) · max 0.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 23, 2026
Affected products added · linux/linux
Oct 23, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 23, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 23, 2026 · Alertas do Telegram
CVE published
Oct 23, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 23, 2026 – Oct 23, 2026
1× Official description updated · Oct 23, 2026 – Oct 23, 2026

References

3 on the record

git.kernel.org/stable/c/888363d74c3b5d32e2accf217add70f8b38e0e2b
NIST National Vulnerability Database
git.kernel.org/stable/c/1a116222acdcc1bc1a8350727ae6f28907d44594
NIST National Vulnerability Database
git.kernel.org/stable/c/9e820a6becdd955a04adbedfd767253a47eedd9e
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-99216 Drivers: hv: Don't reset VMBus connection state on error/exit paths 2d
Unknown CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 2d
Unknown CVE-2026-99207 scsi: target: Disable interrupts while holding delayed_cmd_lock 2d
Unknown CVE-2026-99208 drm/xe/oa: Zero OA buffer at allocation 2d
Unknown CVE-2026-99209 drm/xe: skip eviction of a BO with no resource 2d
Unknown CVE-2026-99210 accel/rocket: clear rdev on device init failure 2d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-98986 is "namespace: remove the fsnotify marks of a mount namespace in process context", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.17% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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