CVE-2026-98268 perf: Fix null pointer access in is_include_guest_event()
A local attacker can cause a kernel crash via null pointer dereference in perf subsystem during module unload with active connections.
- 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-2026-98268?
CVE-2026-98268 is a vulnerability in Linux, published on 6 Oct 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:
perf: Fix null pointer access in is_include_guest_event()
A typical module unload occurring event when there is an active perf connection leads to freeing of the pmu pointer. The call log is something like: .. __pmu_detach_event pmu_detach_event pmu_detach_events perf_pmu_unregister ..
__pmu_detach_event() sets event->pmu to null. When the perf connection finally is closed, the following stack trace is observed:
Oops: general protection fault, kernel NULL pointer dereference ... RIP: 0010:_free_event+0x3e/0x370 ... Call Trace: ... perf_event_release_kernel+0x260/0x2d0 perf_release+0x12/0x20
A call to mediated_pmu_unaccount_event() inside _free_event() is the root cause of this crash. Adding a check inside is_include_guest_event() ensures we don't accidentally access a null pmu ptr. In addition to this, we will now call mediated_pmu_unaccount_event() before clearing the pmu ptr so that nr_include_guest_events counts are maintained correctly.
Which versions are affected by CVE-2026-98268?
How do I fix CVE-2026-98268?
Apply the vendor's patch.
Is CVE-2026-98268 being exploited?
There is no known exploitation of CVE-2026-98268 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-98268, GHSA-47g9-qxgv-4q29, UBUNTU-CVE-2026-98268.