CVE-2023-53687

What it actually does

Memory leak in s3c24xx_serial_getclk() during clock iteration: failure to free either the prior best match on replacement or the new candidate when no replacement occurs.

Why it matters to the business

Gradual memory exhaustion on affected Linux systems using Samsung serial hardware, potentially causing kernel instability, reduced performance, or denial of service over time; low exploitation likelihood but high impact on long-running embedded or server deployments.

How an attack unfolds

An attacker with local access triggers repeated calls to the clock selection routine (e.g., during device probe or configuration changes) to accumulate unfreed clock structures until memory pressure leads to system impact.

How to fix it

Update the Linux kernel to the fixed commit 933e5b2998bc3a527d15efbf1e97c9e63297aa3c or later stable release containing the patch; rebuild and deploy the updated kernel image on affected systems.

How to confirm the fix worked

Confirm presence of the fix commit in the running kernel source or binary; exercise the serial clock selection path under memory accounting tools to verify no incremental leaks; monitor /proc/meminfo or slabinfo for s3c24xx-related objects.

Typical attack path

1. Obtain local code execution or user access on target system
2. Trigger s3c24xx_serial_getclk() via serial device initialization or reconfiguration
3. Repeat the operation to leak clock objects without triggering OOM immediately
4. Monitor for memory pressure or system degradation

How to detect it

Review kernel logs for repeated s3c24xx or tty clock allocation messages; use kmemleak or similar to scan for unreferenced clock objects; correlate with serial device probe events in dmesg or audit logs.

What your security team should do

• Apply the kernel update containing commit 933e5b2998bc3a527d15efbf1e97c9e63297aa3c immediately on all systems using the samsung_tty driver
• Prioritize patching for long-uptime embedded or server fleets where memory leaks accumulate
• Add kernel memory leak detection tooling (e.g., kmemleak) to CI and production monitoring
• Review downstream distributions for backported fixes and schedule updates accordingly