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How the mentioned CVE works
The vulnerability CVE-2025-38303 resides in the Linux kernel’s Bluetooth Extended Inquiry Response (EIR) functionality. The core issue is in the `eir_create_adv_data()` function, which assembles advertising data packets. This function unconditionally attempts to append two specific data types: EIR Flags and EIR TX Power, without first verifying if the target buffer has sufficient space to accommodate them. If the buffer is already near its capacity when these fixed-size elements are added, the write operation will exceed the buffer’s boundary. This results in a heap-based buffer overflow, corrupting adjacent kernel memory. An attacker can exploit this by manipulating Bluetooth advertising procedures, potentially leading to arbitrary code execution within the kernel context with full system privileges or causing a kernel panic for denial-of-service.
DailyCVE
Platform: Linux Kernel
Version: (pre-patch versions)
Vulnerability: Buffer Overflow
Severity: Critical
date: 2025-07-10
Prediction: Patch expected by 2025-08-01
What Undercode Say:
`sudo systemctl status bluetooth`
`cat /proc/version`
`sudo dmesg | grep -i bluetooth`
`git log –grep=”CVE-2025-38303″ –oneline`
How Exploit:
A local attacker or a proximate remote attacker could craft malicious Bluetooth Low Energy (BLE) advertising data packets. When a vulnerable Linux system with Bluetooth active processes this malicious packet, the `eir_create_adv_data` function overflows the heap buffer. This corrupts kernel memory, which can be leveraged to execute arbitrary code with kernel-level (root) privileges, completely compromising the operating system.
Protection from this CVE
Update the Linux kernel to a version containing the official patch. The fix involves adding proper bounds checking in the `eir_create_adv_data()` function before writing the EIR Flags and TX Power data elements. Until patched, disable the Bluetooth adapter if it is not in use.
Impact:
Full system compromise, elevation of privileges to root, denial-of-service (system crash), and potential for remote code execution if the attacker is within Bluetooth range.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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