CVE-2022-45919 is a critical use-after-free vulnerability discovered in the Linux kernel, affecting versions up to 6..10. The issue resides within the drivers/media/dvb-core/dvb_ca_en50221.c file of the kernel, which is responsible for implementing the DVB (Digital Video Broadcasting) subsystem and providing support for the Common Interface (CI) hardware through the EN50221 standard's functions.

This article provides an in-depth analysis of the vulnerability, including the affected code snippet, and demonstrates a method to exploit it. We also provide links to the original references, along with possible solutions and mitigation strategies.

Code Snippet & References

The issue in question lies in the "dvb_ca_en50221.c" file, which can be found in the kernel's source code repository:

The problematic code segment is presented below

static long dvb_ca_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        struct dvb_device *dvbdev = file->private_data;
        struct dvb_ca_private *ca = dvbdev->priv;
        int err = ;

        switch (cmd) {


        case CA_RESET:
                err = dvb_ca_en50221_reset(ca, arg);


        case CA_GET_CAP:
                err = dvb_ca_en50221_get_cap(ca, arg);


        return err;

Exploit Details

The vulnerability arises due to a race condition in the dvb_ca_en50221 implementation that can lead to a use-after-free when a user disconnects from the Common Interface (CI) hardware after opening it. The lack of a wait_event function allows this race condition to manifest, leading to the use-after-free.

An attacker with local access to the vulnerable system could exploit the use-after-free and potentially gain unauthorized access or escalate privileges, leading to the compromise of the target system, affecting the confidentiality, integrity, and availability of the target machine.

Disconnect from the CI hardware without waiting for any event.

3. Perform a sequence of malicious operations targeting the freed memory, causing arbitrary code execution or kernel crashes.

Limit permissions to access the DVB subsystem, preventing unauthorized access.

3. Monitor access logs and system behavior for any suspicious activities indicating an attempt to exploit the vulnerability.


CVE-2022-45919 is a serious use-after-free vulnerability in the Linux kernel's DVB subsystem that could lead to system compromise. In order to provide users with a secure and reliable system, it is essential for administrators to apply necessary patches and implement mitigation strategies to prevent unauthorized exploitation of this vulnerability.


Published on: 11/27/2022 02:15:00 UTC
Last modified on: 02/01/2023 15:07:00 UTC