CVE-2025-68819

What it actually does

Missing bounds check on user-controlled rlen in dtv5100_i2c_msg allows out-of-bounds access into st->data buffer in the DVB-USB driver.

Why it matters to the business

Systems using affected DVB tuner hardware face risk of kernel memory corruption leading to crashes, denial of service, or local privilege escalation; high downstream package prevalence increases exposure surface across distributions.

How an attack unfolds

An attacker with local access crafts an oversized rlen value in an I2C control message sent to the dtv5100 device, bypassing the absent range validation and triggering out-of-bounds memory operations that can be leveraged for code execution or information disclosure.

How to fix it

Upgrade the Linux kernel to commit c2c293ea7b61f12cdaad1e99a5b4efc58c88960a or later; for affected Chromium-based packages apply the versions 143.0.7499.109-r0 or newer that incorporate the corrected driver.

How to confirm the fix worked

Confirm the running kernel contains commit c2c293ea7b61f12cdaad1e99a5b4efc58c88960a; inspect dtv5100_i2c_msg source for the added rlen bounds check against sizeof(st->data); verify package versions match the listed fixed releases.

Typical attack path

1. Obtain local access on a system with a vulnerable dtv5100-based USB tuner
2. Open the DVB device node and prepare a malicious I2C message structure
3. Set rlen larger than sizeof(st->data) and invoke the dtv5100_i2c_msg path
4. Trigger kernel memory corruption and escalate privileges or cause denial of service

How to detect it

Review kernel logs for oops/panic traces referencing dtv5100_i2c_msg or out-of-bounds accesses in the dvb-usb driver; correlate with device attachment events in syslog or audit logs around the time of any instability.

What your security team should do

• Apply kernel and Chromium package updates immediately on all systems exposing DVB-USB hardware
• Restrict local device access via udev rules or module blacklisting until patches are deployed
• Monitor for kernel oops or panic logs involving dtv5100
• Audit systems for presence of dtv5100 USB devices and prioritize patching high-value hosts