Bug 2400749 (CVE-2023-53479)

Summary: CVE-2023-53479 kernel: Linux kernel CXL driver: Use-after-free vulnerability leading to system instability or privilege escalation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's CXL driver. This vulnerability, a use-after-free, allows a local user to cause system instability or a denial of service. The issue arises when the `cxl_parse_cfmws()` function attempts to use memory that has already been released. This could potentially lead to unauthorized access or control over the system.
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Description OSIDB Bzimport 2025-10-01 12:05:16 UTC 
In the Linux kernel, the following vulnerability has been resolved:

cxl/acpi: Fix a use-after-free in cxl_parse_cfmws()

KASAN and KFENCE detected an user-after-free in the CXL driver. This
happens in the cxl_decoder_add() fail path. KASAN prints the following
error:

   BUG: KASAN: slab-use-after-free in cxl_parse_cfmws (drivers/cxl/acpi.c:299)

This happens in cxl_parse_cfmws(), where put_device() is called,
releasing cxld, which is accessed later.

Use the local variables in the dev_err() instead of pointing to the
released memory. Since the dev_err() is printing a resource, change the open
coded print format to use the %pr format specifier.
Comment 1 Jon Moroney 2025-10-01 21:09:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100112-CVE-2023-53479-5c70@gregkh/T