CVE-2024-53062

What it actually does

The vulnerability allows a potential Spectre gadget in mgb4_cmt_set_vin_freq_range() within drivers/media/pci/mgb4/mgb4_cmt.c, where untrusted user-controlled frequency range values from sysfs can be used in array indexing and register writes without proper bounds sanitization, enabling speculative execution side-channel information disclosure.

Why it matters to the business

Systems running affected Linux kernel versions with the mgb4 media driver may be exposed to low-risk information leakage of kernel memory contents, increasing the chance of sensitive data exposure on devices using this hardware; low EPSS and lack of KEV listing indicate limited real-world exploitation urgency despite mentions in broader Linux kernel threat actor campaigns.

How an attack unfolds

An attacker with local access writes crafted frequency values via the sysfs interface to frequency_range_store(), triggering the unsanitized array access in mgb4_cmt_set_vin_freq_range() that creates a Spectre gadget; speculative execution can then leak kernel data through cache side channels, potentially aided by techniques seen in 2024 zero-day espionage and financially motivated campaigns targeting Linux kernel flaws.

How to fix it

Update the Linux kernel to the fixed commit e0bc90742bbd6eb9c63e6c22f8f6e10be7b1e225 or later stable releases that include the Spectre bounds sanitization for mgb4_cmt_set_vin_freq_range(); apply vendor kernel updates promptly for any distributions shipping the mgb4 driver.

How to confirm the fix worked

Verify the running kernel contains commit e0bc90742bbd6eb9c63e6c22f8f6e10be7b1e225 or equivalent backport; confirm absence of the smatch warnings for 'cmt_vals_in' and 'reg_set' in the mgb4_cmt.c source; test that sysfs frequency writes no longer produce out-of-bounds speculative accesses.

Typical attack path

1. Obtain local unprivileged access to a system with the mgb4 driver loaded
2. Identify and write to the frequency_range sysfs attribute under the mgb4 device
3. Supply out-of-bounds index values to trigger speculative execution paths
4. Measure cache timing or other side-channel effects to extract leaked kernel data

How to detect it

Review kernel audit logs and sysfs write events for unusual frequency_range modifications; inspect dmesg or ftrace for mgb4_cmt activity; correlate with process execution of tools that write to /sys devices under media/pci/mgb4; no specific post-exploitation artifacts are publicly tied to this issue.

What your security team should do

• Prioritize kernel updates on any systems exposing the mgb4 PCI media driver
• Monitor EPSS and threat actor reports for any increase in Linux kernel Spectre-style exploits
• Restrict unprivileged sysfs access to media device attributes where feasible
• Include the mgb4 driver in regular kernel patch validation and regression testing