Bug 2407330 (CVE-2025-40089)

Summary: CVE-2025-40089 kernel: cxl/features: Add check for no entries in cxl_feature_info
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-10-30 10:01:51 UTC 
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.
Comment 1 Jon Moroney 2025-10-30 16:47:58 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025103015-CVE-2025-40089-26ca@gregkh/T