CVE-2023-54093 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
media: anysee: fix null-ptr-deref in anysee_master_xfer
In anysee_master_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 anysee_master_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()")
[hverkuil: add spaces around +]
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 01/03/2026
The vulnerability CVE-2023-54093 represents a critical null pointer dereference flaw within the Linux kernel's media subsystem, specifically affecting the anysee driver component. This issue resides in the anysee_master_xfer function which handles I2C transfer operations for anysee USB video capture devices. The vulnerability stems from inadequate input validation where user-controlled data flows directly into kernel space without proper sanitization. The flaw manifests when processing I2C messages where msg[i].buf can be null while msg[i].len remains zero, bypassing existing validation checks that should prevent such conditions from reaching the critical code path. This particular scenario creates a dangerous condition where maliciously crafted I2C messages can trigger a null pointer dereference when the code attempts to access msg[i].buf[0] without verifying that the buffer pointer is valid.
The technical implementation of this vulnerability demonstrates a classic security flaw in kernel driver development where insufficient bounds checking and input validation lead to exploitable conditions. The anysee_master_xfer function processes I2C messages through a loop structure that iterates over user-provided message arrays, with each message containing buffer pointers and length specifications. When the validation logic fails to properly check the length field in conjunction with the buffer pointer, it allows for a scenario where a null buffer pointer is processed with a zero length, effectively creating a condition where dereferencing the null pointer becomes inevitable. This type of vulnerability directly aligns with CWE-476 which describes null pointer dereference conditions, and represents a clear violation of secure coding practices in kernel space development where all user inputs must be rigorously validated before processing.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling denial of service attacks against systems utilizing anysee USB video capture devices. An attacker with local access or the ability to inject malicious I2C commands could exploit this flaw to cause kernel panics or system instability, effectively rendering the affected system unusable. The vulnerability affects systems running Linux kernels with the anysee driver enabled, particularly those using USB video capture hardware that relies on this specific driver implementation. Given that USB video capture devices are commonly used in various applications including security cameras, streaming equipment, and embedded systems, the potential attack surface for this vulnerability is significant. The exploitation scenario requires minimal privileges and can be executed through normal I2C communication channels, making it particularly concerning for embedded systems and IoT devices that may not have robust security measures in place.
The fix implemented for this vulnerability follows established security patterns and best practices for kernel driver development. The solution involves adding explicit validation checks on msg[i].len to prevent processing of null buffer pointers, which directly addresses the root cause of the issue. This approach mirrors the mitigation strategy used in a similar fix for the dvb-usb az6027 driver, demonstrating a consistent methodology across kernel subsystems for handling similar null pointer dereference scenarios. The fix requires that anysee_master_xfer function validate both the buffer pointer and length fields before attempting any memory access operations, ensuring that the code path will not proceed with invalid buffer references. This mitigation aligns with the ATT&CK framework's defense evasion techniques by preventing malicious input from reaching vulnerable code paths, and follows the principle of least privilege by ensuring all kernel operations validate their inputs thoroughly. The fix also demonstrates adherence to secure coding standards by implementing proper input sanitization and error handling mechanisms that prevent exploitation of similar vulnerabilities in related components.