CVE-2026-45968 cpuidle: Skip governor when only one idle state is available
A null pointer dereference in the Linux kernel cpuidle governor causes a system crash on specific PowerNV platforms with a single idle state.
- 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-2026-45968?
CVE-2026-45968 is a medium-severity vulnerability in Linux kernel, published on 27 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:
cpuidle: Skip governor when only one idle state is available
On certain platforms (PowerNV systems without a power-mgt DT node), cpuidle may register only a single idle state. In cases where that single state is a polling state (state 0), the ladder governor may incorrectly treat state 1 as the first usable state and pass an out-of-bounds index. This can lead to a NULL enter callback being invoked, ultimately resulting in a system crash.
[ 13.342636] cpuidle-powernv : Only Snooze is available [ 13.351854] Faulting instruction address: 0x00000000 [ 13.376489] NIP [0000000000000000] 0x0 [ 13.378351] LR [c000000001e01974] cpuidle_enter_state+0x2c4/0x668
Fix this by adding a bail-out in cpuidle_select() that returns state 0 directly when state_count <= 1, bypassing the governor and keeping the tick running.
Weakness: CWE-476
Which versions are affected by CVE-2026-45968?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-45968?
Apply the vendor's patch.
Is CVE-2026-45968 being exploited?
There is no known exploitation of CVE-2026-45968 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-45968, DEBIAN-CVE-2026-45968, GHSA-2g8g-2643-4335, ROOT-OS-UBUNTU-2204-CVE-2026-45968, ROOT-OS-UBUNTU-2404-CVE-2026-45968, UBUNTU-CVE-2026-45968.