CVE-2023-3359

What it actually does

Missing validation of the kzalloc return value in brcm_nvram_parse allows a NULL pointer dereference when memory allocation fails under low-memory conditions.

Why it matters to the business

Local denial-of-service crashes on affected Linux systems can interrupt services and require manual restarts, increasing operational overhead especially on embedded or resource-constrained devices.

How an attack unfolds

An attacker with local access triggers the brcm_nvram_parse function during NVRAM parsing while the system is under memory pressure, causing kzalloc to return NULL; the subsequent dereference produces a kernel panic.

How to fix it

Update the Linux kernel to the commit b0576ade3aaf24b376ea1a4406ae138e2a22b0c0 or later that adds the missing NULL check after kzalloc in drivers/nvmem/brcm_nvram.c.

How to confirm the fix worked

Verify the presence of the NULL check after kzalloc in brcm_nvram_parse by inspecting the source or confirming the running kernel contains commit b0576ade3aaf24b376ea1a4406ae138e2a22b0c0; attempt to trigger the function under memory pressure to confirm no crash occurs.

Typical attack path

1. Obtain local user access on the target Linux system
2. Force memory exhaustion or trigger the NVRAM parsing code path
3. Invoke brcm_nvram_parse without a successful kzalloc allocation
4. Trigger NULL pointer dereference resulting in kernel oops or panic

How to detect it

Search kernel logs for oops or panic messages referencing brcm_nvram_parse or drivers/nvmem/brcm_nvram.c; correlate with low-memory conditions or NVRAM access events.

• brcm_nvram_parse
• drivers/nvmem/brcm_nvram.c
• NULL pointer dereference in kzalloc path

What your security team should do

• Apply the referenced kernel commit or a distribution backport immediately on all affected systems
• Monitor for kernel oops reports involving brcm_nvram_parse
• Limit local user access where possible until patches are deployed