CVE-2026-46106 eventfs: Hold eventfs_mutex and SRCU when remount walks events
A race condition in the Linux kernel eventfs subsystem allows local attackers to cause a system crash via concurrent remount and event removal operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46106?
CVE-2026-46106 is a medium-severity vulnerability in Linux kernel, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
eventfs: Hold eventfs_mutex and SRCU when remount walks events
Commit 340f0c7067a9 ("eventfs: Update all the eventfs_inodes from the events descriptor") had eventfs_set_attrs() recurse through ei->children on remount. The walk only holds the rcu_read_lock() taken by tracefs_apply_options() over tracefs_inodes, which is wrong:
- list_for_each_entry over ei->children races with the list_del_rcu() in eventfs_remove_rec() -- LIST_POISON1 deref, same shape as d2603279c7d6. - eventfs_inodes are freed via call_srcu(&eventfs_srcu, ...). rcu_read_lock() does not extend an SRCU grace period, so ti->private can be reclaimed under the walk. - The writes to ei->attr race with eventfs_set_attr(), which holds eventfs_mutex.
Reproducer:
while :; do mount -o remount,uid=$((RANDOM%1000)) /sys/kernel/tracing; done & while :; do echo "p:kp submit_bio" > /sys/kernel/tracing/kprobe_events echo > /sys/kernel/tracing/kprobe_events done
Wrap the events portion of tracefs_apply_options() in eventfs_remount_lock()/_unlock() that take eventfs_mutex and srcu_read_lock(&eventfs_srcu). eventfs_set_attrs() doesn't sleep so the nested rcu_read_lock() is fine; lockdep_assert_held() pins the contract.
Comment in tracefs_drop_inode() said "RCU cycle" -- it is SRCU.
Which versions are affected by CVE-2026-46106?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46106?
Apply the vendor's patch.
Is CVE-2026-46106 being exploited?
There is no known exploitation of CVE-2026-46106 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88953, BELL-CVE-2026-46106, DEBIAN-CVE-2026-46106, GHSA-vr2g-5q36-7736, ROOT-OS-UBUNTU-2404-CVE-2026-46106, UBUNTU-CVE-2026-46106.