CVE-2024-56767

What it actually does

Null pointer dereference in dmaengine at_xdmac driver when at_xdmac_memset_create_desc returns NULL due to invalid len or exhausted free_descs_list, leading to kernel crash or memory corruption.

Why it matters to the business

Potential denial of service or system instability on Linux systems using the affected DMA engine, increasing operational risk and requiring urgent patching across dependent environments.

How an attack unfolds

An attacker supplies crafted DMA memset parameters that cause at_xdmac_memset_create_desc to fail and return NULL, resulting in immediate dereference; listed threat actors in 2024 zero-day campaigns and Linux kernel access vulnerabilities have targeted similar kernel flaws for local privilege escalation or crash.

How to fix it

Update chromium-browser on Ubuntu 14.04 LTS to version 53.0.2785.143-0ubuntu0.14.04.1.1142 or later; apply equivalent kernel updates containing the fix for at_xdmac_prep_dma_memset.

How to confirm the fix worked

Confirm package version matches or exceeds the listed fixed release; review kernel logs for absence of null pointer dereference patterns in at_xdmac after upgrade.

Typical attack path

1. Identify system using at_xdmac DMA engine
2. Trigger DMA memset operation with invalid length or under memory pressure
3. Force at_xdmac_memset_create_desc to return NULL
4. Trigger null pointer dereference to crash kernel or attempt further exploitation

How to detect it

Review kernel logs for at_xdmac null pointer dereference messages; correlate with DMA activity from processes; check for exploitation patterns associated with listed threat actors targeting Linux kernel resource issues.

What your security team should do

• Prioritize patching within CISA timelines if applicable despite non-KEV status
• Scan for affected chromium-browser and kernel packages across all Linux hosts
• Monitor EPSS trend stability and threat actor activity on similar kernel issues