CVE-2023-53496
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BaseFortify

Publication date: 2025-10-01

Last updated on: 2026-01-16

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: x86/platform/uv: Use alternate source for socket to node data The UV code attempts to build a set of tables to allow it to do bidirectional socket<=>node lookups. But when nr_cpus is set to a smaller number than actually present, the cpu_to_node() mapping information for unused CPUs is not available to build_socket_tables(). This results in skipping some nodes or sockets when creating the tables and leaving some -1's for later code to trip. over, causing oopses. The problem is that the socket<=>node lookups are created by doing a loop over all CPUs, then looking up the CPU's APICID and socket. But if a CPU is not present, there is no way to start this lookup. Instead of looping over all CPUs, take CPUs out of the equation entirely. Loop over all APICIDs which are mapped to a valid NUMA node. Then just extract the socket-id from the APICID. This avoid tripping over disabled CPUs.
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Meta Information
Published
2025-10-01
Last Modified
2026-01-16
Generated
2026-05-07
AI Q&A
2025-10-01
EPSS Evaluated
2026-05-05
NVD
CVE-2023-53496
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.5 (inc) to 6.5.5 (exc)
linux linux_kernel 6.6
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-NVD-CWE-noinfo
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's UV platform code, where it attempts to build tables for bidirectional socket-to-node lookups. When the number of CPUs (nr_cpus) is set smaller than the actual number present, the mapping information for unused CPUs is missing. This causes the building function to skip some nodes or sockets and leave invalid entries (-1), which later causes kernel crashes (oopses). The issue arises because the code loops over all CPUs to create these lookups, but if a CPU is not present, the lookup cannot start. The fix involves changing the approach to loop over all APICIDs mapped to valid NUMA nodes instead of CPUs, avoiding problems with disabled CPUs.


How can this vulnerability impact me? :

This vulnerability can cause kernel crashes (oopses) due to invalid socket-to-node lookup tables when the system's CPU configuration is inconsistent. Such crashes can lead to system instability, unexpected reboots, or downtime, potentially affecting system availability and reliability.


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