CVE-2024-50074

What it actually does

The parport driver used snprintf() for length calculations when formatting output, which returns the would-be size rather than actual bytes written, allowing array out-of-bounds access and potential buffer overflow.

Why it matters to the business

Linux systems may experience kernel crashes, memory corruption, or arbitrary code execution in printer port handling code, with low immediate risk due to absence from known exploited lists and stable EPSS.

How an attack unfolds

An attacker supplies crafted data to parport interfaces that triggers oversized formatting operations; the incorrect length math from snprintf permits writes beyond buffer limits, leading to corruption or control flow hijacking.

How to fix it

Update Linux kernel to fixed versions including 4.19.323 or apply commit 8aadef73ba3b325704ed5cfc4696a25c350182cf; for affected eglibc packages on Ubuntu 14.04 LTS upgrade to 2.19-0ubuntu6.8.

How to confirm the fix worked

Verify running kernel version against fixed releases, inspect parport source for scnprintf usage in formatting paths, and confirm absence of the vulnerable snprintf length calculations.

Typical attack path

1. Identify system exposing parport interfaces or related sysfs/proc entries
2. Craft input exceeding expected buffer sizes for formatting routines
3. Trigger snprintf-based length calculation that underestimates actual output
4. Overwrite adjacent memory structures to achieve code execution or denial of service

How to detect it

Review kernel logs and audit trails for parport-related crashes or memory faults around formatting operations; correlate with process activity involving printer or parallel port access.

What your security team should do

• Prioritize kernel upgrades on all systems using parport or printer port functionality
• Monitor for new kernel releases containing the scnprintf fix across stable branches
• Apply least-privilege restrictions on access to parport devices where possible
• Include kernel version checks in vulnerability scanning and asset inventory processes