CVE-2026-43416 powerpc, perf: Check that current->mm is alive before getting user callchain
A missing null check in the Linux kernel's PowerPC performance monitoring code allows a local attacker to trigger a kernel panic via a BPF program.
- 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-2026-43416?
CVE-2026-43416 is a medium-severity vulnerability in Linux kernel, published on 8 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:
powerpc, perf: Check that current->mm is alive before getting user callchain
It may happen that mm is already released, which leads to kernel panic. This adds the NULL check for current->mm, similarly to commit 20afc60f892d ("x86, perf: Check that current->mm is alive before getting user callchain").
I was getting this panic when running a profiling BPF program (profile.py from bcc-tools):
[26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0) [26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588 [26215.051952] Faulting instruction address: 0xc00000000020fac0 [26215.051957] Oops: Kernel access of bad area, sig: 11 [#1] [...] [26215.052049] Call Trace: [26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable) [26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30 [26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360 [26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0 [26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274 [...]
In addition, move storing the top-level stack entry to generic perf_callchain_user to make sure the top-evel entry is always captured, even if current->mm is NULL.
[Maddy: fixed message to avoid checkpatch format style error]
Weakness: CWE-476
Which versions are affected by CVE-2026-43416?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43416?
Apply the vendor's patch.
Is CVE-2026-43416 being exploited?
There is no known exploitation of CVE-2026-43416 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43416, DEBIAN-CVE-2026-43416, GHSA-xw48-xgg9-9h3g, ROOT-OS-DEBIAN-11-CVE-2026-43416, ROOT-OS-DEBIAN-12-CVE-2026-43416, ROOT-OS-DEBIAN-13-CVE-2026-43416 and 3 more.