CVE-2026-98988 Linux Kernel - Broken Access Control

Linux kernel contains a privilege escalation vulnerability caused by improper handling of covered mounts in open_tree(OPEN_TREE_NAMESPACE), letting unprivileged users bypass mount namespace restrictions, exploit requires unprivileged user creating a user namespace first.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.20% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Privilege Escalation, Information Disclosure
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Published
23 October 2026
Updated
25 October 2026

Vendor fix

Update to the latest Linux kernel version containing the fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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