CVE-2026-68177 tracing: Delay module ref count for "enable_event" trigger
A use-after-free in the Linux kernel tracing subsystem allows attackers to execute arbitrary code or escalate privileges by triggering module removal during event processing.
- 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-2026-68177?
CVE-2026-68177 is a high-severity use after free vulnerability in Linux, published on 10 Aug 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:
tracing: Delay module ref count for "enable_event" trigger
Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately.
It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug.
Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished.
Which versions are affected by CVE-2026-68177?
How do I fix CVE-2026-68177?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-68177 being exploited?
There is no known exploitation of CVE-2026-68177 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-68177, GHSA-h49p-x9p9-q3f3, UBUNTU-CVE-2026-68177.