CVE-2025-68819: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-68819 is an out-of-bounds memory access vulnerability in the Linux kernel's media/dvb-usb/dtv5100 driver, specifically within the dtv5100_i2c_msg() function. The vulnerability arises because the user-controlled rlen parameter is not validated against the size of the st->data buffer before use, allowing an oversized value to trigger an out-of-bounds write. It was published on January 13, 2026, and affects Linux kernel versions from commit 60688d5e6e6e up to the patched stable releases. No CVSS score has been assigned by NVD at this time; the ENISA base score is listed as 0.0 and the EPSS score is approximately 0.018% (Red Hat CVE, Feedly).

The root cause is a missing bounds check (CWE classification not formally assigned by NVD) on the rlen parameter in dtv5100_i2c_msg() within the drivers/media/usb/dvb-usb/dtv5100.c driver. Because rlen is derived from user-controlled input and is used directly to determine how many bytes are read into the fixed-size st->data buffer, supplying a value larger than sizeof(st->data) causes an out-of-bounds memory access. Exploitation requires local access to a system with a DTV5100 DVB-USB device attached and the ability to issue I2C messages to the driver. The fix adds proper range checking to clamp rlen to the buffer size before any memory operation is performed (Red Hat CVE, Feedly).

Successful exploitation could lead to out-of-bounds memory reads or writes in kernel space, potentially resulting in information disclosure of sensitive kernel memory, system instability or crashes (denial of service), or privilege escalation depending on memory layout and attacker capabilities. The vulnerability is scoped to systems with DVB-USB DTV5100 hardware attached, limiting the affected asset population. Lateral movement potential is low, but kernel-level compromise could allow an attacker to undermine all security boundaries on the affected host (Feedly).

The Linux kernel has released patches addressing this vulnerability in the following stable versions: 6.1.160, 6.6.120, 6.12.64, 6.18.3, and 6.19-rc1 and later. Downstream distributions including Debian, Ubuntu (USN-8177-1, USN-8177-2, USN-8183-1, USN-8183-2, USN-8245-1, USN-8257-1), SUSE, and Oracle Linux have also issued updated kernel packages. As a workaround for systems where immediate kernel updates are not feasible, administrators should consider disabling or restricting access to DVB-USB devices if they are not actively required (Feedly, Ubuntu USN-8177-1, Debian LTS).