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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17
Weakness: CWE-476

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.

Affected products

Linux kernel: from 2.6.33 before 4.9.311; from 4.10 before 4.14.276; from 4.15 before 4.19.239; from 4.20 before 5.4.190; from 5.5 before 5.10.112; from 5.11 before 5.15.35 — fixed in 4.14.276, 4.19.239, 4.9.311, 5.10.112, 5.15.35, 5.17.4

How to fix

Upgrade to a fixed version: Linux kernel 4.14.276, 4.19.239, 4.9.311, 5.10.112. Check the vendor advisory for mitigations.

References

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