CVE-2023-54314 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
media: af9005: Fix null-ptr-deref in af9005_i2c_xfer
In af9005_i2c_xfer, msg is controlled by user. When msg[i].buf
is null and msg[i].len is zero, former checks on msg[i].buf would be
passed. Malicious data finally reach af9005_i2c_xfer. If accessing msg[i].buf[0] without sanity check, null ptr deref would happen.
We add check on msg[i].len to prevent crash.
Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")
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Analysis
by VulDB Data Team • 06/07/2026
The vulnerability identified as CVE-2023-54314 resides within the Linux kernel's media subsystem, specifically affecting the af9005 DVB USB driver. This flaw represents a classic null pointer dereference issue that occurs during I2C transfer operations, demonstrating a critical weakness in input validation and memory safety practices. The vulnerability manifests in the af9005_i2c_xfer function where user-controlled data flows directly into kernel space without proper sanitization, creating an exploitable condition that could lead to system instability or potential privilege escalation.
The technical root cause stems from inadequate validation of I2C message structures within the af9005 driver implementation. When processing user-supplied I2C messages, the code fails to properly check the length field of message buffers before attempting to access memory locations. Specifically, the vulnerability occurs when msg[i].buf is null but msg[i].len equals zero, a condition that bypasses existing validation checks. This scenario allows malicious actors to craft specially crafted I2C messages that trigger a null pointer dereference when the code attempts to access msg[i].buf[0] without proper bounds checking. The flaw aligns with CWE-476 which defines null pointer dereference as a common software vulnerability pattern that can lead to crashes or arbitrary code execution.
This vulnerability operates at the kernel level within the media subsystem, specifically affecting DVB USB devices that utilize the af9005 driver. The operational impact includes potential system crashes, denial of service conditions, and in worst-case scenarios, privilege escalation opportunities that could allow attackers to gain elevated system privileges. The attack surface is particularly concerning as it involves user-space to kernel-space data transfer mechanisms, making it accessible through legitimate device interaction pathways. The vulnerability's exploitation requires minimal privileges and can be triggered through standard I2C communication protocols, making it a significant concern for embedded systems and devices that rely on DVB USB functionality.
The fix implemented addresses the core issue by adding explicit checks on msg[i].len to prevent the null pointer dereference condition. This remediation follows established patterns from similar vulnerabilities within the same codebase, as evidenced by the referenced commit 0ed554fd769a that resolved an identical issue in the az6027_i2c_xfer function. The solution demonstrates proper defensive programming practices that align with the ATT&CK framework's defense evasion techniques, specifically targeting the prevention of kernel-level crashes through input validation. System administrators should prioritize updating affected kernel versions and implementing proper kernel lockdown mechanisms to mitigate exploitation risks. The vulnerability highlights the importance of comprehensive input validation in kernel drivers and serves as a reminder of the critical security implications that can arise from seemingly simple memory access patterns in device drivers.