CVE-2021-47631 [Medium] | Security Vulnerability in Linux Kernel

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.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-11-21	0.06%	0.03%	-0.03%
2	2025-11-18	0.04%	0.06%	+0.01%
3	2025-02-27	—	0.04%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-11-21

0.06%

0.03%

-0.03%

2025-11-18

0.04%

0.06%

+0.01%

2025-02-27

—

0.04%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

134c704f-9b21-4f2e-91b3-4a467353bcc0

OS Trackers for CVE-2021-47631

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2021-47631 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-47631
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-47631
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2021-47631/
`ubuntu`	medium	CVE-2021-47631 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, ignored 149, released 145, not-affected 108, needed 4.	https://ubuntu.com/security/CVE-2021-47631

Affected software / configurations for CVE-2021-47631

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 2.6.33, < 4.9.311	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.10, < 4.14.276	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.15, < 4.19.239	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.20, < 5.4.190	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.5, < 5.10.112	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.35	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 5.17.4	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.18	cpe:2.3:o:linux:linux_kernel:5.18:rc1::::::
linux	linux_kernel	5.18	cpe:2.3:o:linux:linux_kernel:5.18:rc2::::::

References for CVE-2021-47631

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

URL

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

Exploit prediction scoring system (EPSS) score for CVE-2021-47631

Common vulnerability scoring system (CVSS) metrics for CVE-2021-47631

Weakness enumeration for CVE-2021-47631

OS Trackers for CVE-2021-47631

Affected software / configurations for CVE-2021-47631

References for CVE-2021-47631