CVE-2026-93263
Received Received - Intake

NULL Pointer Dereference in Linux Kernel Clock Subsystem

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: clk: eswin: Zero-initialize stack-allocated clk_init_data eswin_clk_register_pll() and eswin_register_clkdiv() declare a struct clk_init_data on the stack and only initialize some of its fields (parent_data respectively parent_hws). clk_core_populate_parent_map() checks parent_names first and parent_data second before falling back to parent_hws, so leftover stack garbage in the uninitialized fields hijacks parent resolution and the clk core dereferences a bogus pointer: Unable to handle kernel NULL pointer dereference at virtual address 000000000000000c Oops [#1] epc : __clk_register+0x31a/0x7f0 [<ffffffff805dc774>] __clk_register+0x31a/0x7f0 [<ffffffff805dcd76>] devm_clk_hw_register+0x2a/0x94 [<ffffffff805e319a>] eswin_register_clkdiv+0x80/0xd0 [<ffffffff805e34a0>] eswin_clk_register_clks+0x162/0x1a0 [<ffffffff805e3736>] eic7700_clk_probe+0x146/0x180 [<ffffffff8065d23c>] platform_probe+0x3c/0x7a Observed on EIC7700 hardware (with the driver backported to a 6.17 tree); whether the bug triggers depends entirely on what the stack happens to contain when the registration helpers run. Zero-initialize both structures.

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-25
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-93263
EUVD
EUVD-2026-86135

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability where two functions declare a stack-allocated structure but only initialize some fields. Uninitialized fields may contain leftover stack data, causing the kernel to dereference invalid pointers during clock registration. This leads to kernel crashes like NULL pointer dereferences.

Detection Guidance

This vulnerability is specific to the Linux kernel's eswin clock driver and may not have direct network detection methods. Check kernel logs for NULL pointer dereference errors or oops messages related to clock registration. Commands like dmesg | grep -i 'clk\|oops\|NULL' or journalctl -k | grep -i 'clk\|oops\|NULL' may help identify crashes.

Impact Analysis

If exploited, this bug can crash the system by triggering kernel NULL pointer dereferences. It affects systems using EIC7700 hardware with the vulnerable driver, potentially causing instability or denial of service. The impact depends on stack memory contents at runtime.

Compliance Impact

This vulnerability is a kernel-level memory corruption issue that could lead to system crashes or undefined behavior due to uninitialized memory in clock driver structures. It does not directly affect data privacy or security controls required by standards like GDPR or HIPAA, as it is not a data exposure or access control flaw.

Mitigation Strategies

Update your Linux kernel to a patched version that includes the fix for CVE-2026-93263. If a patched kernel is unavailable, avoid using the eswin clock driver or apply the patch manually by zero-initializing the clk_init_data structures in eswin_clk_register_pll() and eswin_register_clkdiv().

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