CVE-2021-47293

In the Linux kernel, the following vulnerability has been resolved: net/sched: act_skbmod: Skip non-Ethernet packets Currently tcf_skbmod_act() assumes that packets use Ethernet as their L2 protocol, which is not always the case. As an example, for CAN devices: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocol ip prio 10 \ matchall action skbmod swap mac Doing the above silently corrupts all the packets. Do not perform skbmod actions for non-Ethernet packets.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b	Patch
https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d	Patch
https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6	Patch
https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024	Patch
https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c	Patch
https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b	Patch
https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d	Patch
https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6	Patch
https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024	Patch
https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:5.14:rc1::::::
	cpe:2.3:o:linux:linux_kernel:5.14:rc2::::::

History

07 May 2025, 17:51

Type	Values Removed	Values Added
References	~~() https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b -~~	() https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b - Patch
References	~~() https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d -~~	() https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d - Patch
References	~~() https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6 -~~	() https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6 - Patch
References	~~() https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024 -~~	() https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024 - Patch
References	~~() https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c -~~	() https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c - Patch
CWE		NVD-CWE-noinfo
CPE		cpe:2.3:o:linux:linux_kernel:5.14:rc1:::::: cpe:2.3:o:linux:linux_kernel:::::::: cpe:2.3:o:linux:linux_kernel:5.14:rc2::::::
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.8
First Time		Linux linux Kernel Linux

21 Nov 2024, 06:35

Type	Values Removed	Values Added
References	~~() https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b -~~	() https://git.kernel.org/stable/c/071729150be9e1d1b851b70efb6d91ee9269d57b -
References	~~() https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d -~~	() https://git.kernel.org/stable/c/34f1e1f657fae2891b485a3b2b95fe4d2aef9f0d -
References	~~() https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6 -~~	() https://git.kernel.org/stable/c/727d6a8b7ef3d25080fad228b2c4a1d4da5999c6 -
References	~~() https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024 -~~	() https://git.kernel.org/stable/c/a88414fb1117f2fe65fb88e45ba694e1d09d5024 -
References	~~() https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c -~~	() https://git.kernel.org/stable/c/e4fdca366806f6bab374d1a95e626a10a3854b0c -
Summary		(es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/sched: act_skbmod: omitir paquetes que no sean Ethernet. Actualmente, tcf_skbmod_act() asume que los paquetes usan Ethernet como protocolo L2, lo cual no siempre es el caso. Como ejemplo, para dispositivos CAN: $ ip link add dev vcan0 type vcan $ ip link set up vcan0 $ tc qdisc add dev vcan0 root handle 1: htb $ tc filter add dev vcan0 parent 1: protocolo ip prio 10 \ matchall action skbmod swap mac Hacer lo anterior corrompe silenciosamente todos los paquetes. No realice acciones de skbmod para paquetes que no sean Ethernet.

21 May 2024, 15:15

Type	Values Removed	Values Added
New CVE

Information

Published : 2024-05-21 15:15

Updated : 2025-05-07 17:51

NVD link : CVE-2021-47293

Mitre link : CVE-2021-47293

CVE.ORG link : CVE-2021-47293

JSON object : View

Products Affected

linux

linux_kernel

CWE

NVD-CWE-noinfo

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7.8 /10