CVE-2026-98976

In the Linux kernel, the following vulnerability has been resolved: namespace: keep the lock on a mount that a propagated copy is moved beneath attach_recursive_mnt() transfers MNT_LOCKED from the top mount to the mount that is moved beneath it with MOVE_MOUNT_BENEATH. This allows the owner of a user namespace to replace its locked /proc or its root. The mount beneath takes on the job of covering the underlying mountpoint allowing the top mount to be unmounted. Consider two mount namespaces: (H) The host H has a shared mount P with a secret in P/d (Z) Z is a user namespace made from M. Its copy of P receives propagation from the host's P and its copy of M's cover on P/d is locked Z's owner must not get to see P/d. Now (H) mounts X on P/d. This propagates into (Z). The copy of X lands beneath (Z)'s locked cover. The locked property is transfered from (Z)'s cover to the copy of X propagated beneath it. The cover is now unlocked. Now (H) unmounts X again. The copy of X in (Z) gets unmounted and the covering mount is left unlocked on top of P/d. (Z) can now unmount it: Z: umount2(P/d) = EINVAL /* the cover is locked */ H: mount X on P/d, umount X /* both propagate into Z /* Z: umount2(P/d) = 0 /* the cover is now unlocked */ Z: read P/d/secret = "covered-by-root" /* secret revealed */ So only transfer the locked property to the mount beneath for mounts the caller has placed. A propagated copy that lands beneath a locked mount is locked as well so that the mount at the bottom of the stack carries a lock the way every check expects. The mount on top of it remains locked to ensure that it keeps covering even if the propagated mount is unmounted again.

• https://git.kernel.org/stable/c/d74d66aa708ccf2bc0b1e265a83fed0f2308d5c4
• https://git.kernel.org/stable/c/f1f0c24ca701d7d3061c7f69f7450f1734c11745

Published

Oct 23, 2026

Last Modified

Oct 24, 2026

Status

Received

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2026-98970In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98971In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98972In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98973In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98974In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-98975In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2026-98977In the Linux kernel, the following vulnerability has been re…
• CVE-2026-98978In the Linux kernel, the following vulnerability has been re…8.4
• CVE-2026-98979In the Linux kernel, the following vulnerability has been re…
• CVE-2026-9898Insufficient validation of untrusted input in GPU in Google …8.3
• CVE-2026-98980In the Linux kernel, the following vulnerability has been re…8.8
• CVE-2026-98981In the Linux kernel, the following vulnerability has been re…8.8