CVE-2025-40089 cxl/features: Add check for no entries in cxl_feature_info
A null pointer dereference in the Linux kernel CXL feature handling allows local attackers to cause a system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-40089?
CVE-2025-40089 is a vulnerability in Linux, published on 30 Oct 2025. 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:
cxl/features: Add check for no entries in cxl_feature_info
cxl EDAC calls cxl_feature_info() to get the feature information and if the hardware has no Features support, cxlfs may be passed in as NULL.
[ 51.957498] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 51.965571] #PF: supervisor read access in kernel mode [ 51.971559] #PF: error_code(0x0000) - not-present page [ 51.977542] PGD 17e4f6067 P4D 0 [ 51.981384] Oops: Oops: 0000 [#1] SMP NOPTI [ 51.986300] CPU: 49 UID: 0 PID: 3782 Comm: systemd-udevd Not tainted 6.17.0dj test+ #64 PREEMPT(voluntary) [ 51.997355] Hardware name: <removed> [ 52.009790] RIP: 0010:cxl_feature_info+0xa/0x80 [cxl_core]
Add a check for cxlfs before dereferencing it and return -EOPNOTSUPP if there is no cxlfs created due to no hardware support.
Which versions are affected by CVE-2025-40089?
How do I fix CVE-2025-40089?
Apply the vendor's patch.
Is CVE-2025-40089 being exploited?
There is no known exploitation of CVE-2025-40089 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-40089, DEBIAN-CVE-2025-40089, GHSA-c72w-7535-v29m, UBUNTU-CVE-2025-40089.