CVE-2025-21920

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2025-21920
In the Linux kernel, the following vulnerability has been resolved: vlan: enforce underlying device type Currently, VLAN devices can be created on top of non-ethernet devices. Besides the fact that it doesn't make much sense, this also causes a bug which leaks the address of a kernel function to usermode. When creating a VLAN device, we initialize GARP (garp_init_applicant) and MRP (mrp_init_applicant) for the underlying device. As part of the initialization process, we add the multicast address of each applicant to the underlying device, by calling dev_mc_add. __dev_mc_add uses dev->addr_len to determine the length of the new multicast address. This causes an out-of-bounds read if dev->addr_len is greater than 6, since the multicast addresses provided by GARP and MRP are only 6 bytes long. This behaviour can be reproduced using the following commands: ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo ip l set up dev gretest ip link add link gretest name vlantest type vlan id 100 Then, the following command will display the address of garp_pdu_rcv: ip maddr show | grep 01:80:c2:00:00:21 Fix the bug by enforcing the type of the underlying device during VLAN device initialization.

7.1 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 5.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/0fb7aa04c19eac4417f360a9f7611a60637bdacc Patch
https://git.kernel.org/stable/c/30e8aee77899173a82ae5ed89f536c096f20aaeb Patch
https://git.kernel.org/stable/c/3561442599804905c3defca241787cd4546e99a7 Patch
https://git.kernel.org/stable/c/5a515d13e15536e82c5c7c83eb6cf5bc4827fee5 Patch
https://git.kernel.org/stable/c/7f1564b2b2072b7aa1ac75350e9560a07c7a44fd Patch
https://git.kernel.org/stable/c/b33a534610067ade2bdaf2052900aaad99701353 Patch
https://git.kernel.org/stable/c/b6c72479748b7ea09f53ed64b223cee6463dc278 Patch
https://git.kernel.org/stable/c/fa40ebef69234e39ec2d26930d045f2fb9a8cb2b 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:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*
History

11 Apr 2025, 13:13

Type Values Removed Values Added
CWE CWE-125
First Time Linux linux Kernel
Linux
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 7.1
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: vlan: imponer el tipo de dispositivo subyacente Actualmente, los dispositivos VLAN se pueden crear sobre dispositivos que no sean Ethernet. Además del hecho de que no tiene mucho sentido, esto también causa un error que filtra la dirección de una función del kernel al modo de usuario. Al crear un dispositivo VLAN, inicializamos GARP (garp_init_applicant) y MRP (mrp_init_applicant) para el dispositivo subyacente. Como parte del proceso de inicialización, agregamos la dirección de multidifusión de cada solicitante al dispositivo subyacente, llamando a dev_mc_add. __dev_mc_add usa dev->addr_len para determinar la longitud de la nueva dirección de multidifusión. Esto causa una lectura fuera de los límites si dev->addr_len es mayor que 6, ya que las direcciones de multidifusión proporcionadas por GARP y MRP solo tienen 6 bytes de longitud. Este comportamiento se puede reproducir utilizando los siguientes comandos: ip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo ip l set up dev gretest ip link add link gretest name vlantest type vlan id 100 Luego, el siguiente comando mostrará la dirección de garp_pdu_rcv: ip maddr show | grep 01:80:c2:00:00:21 Corrija el error aplicando el tipo de dispositivo subyacente durante la inicialización del dispositivo VLAN.
CPE cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*
References () https://git.kernel.org/stable/c/0fb7aa04c19eac4417f360a9f7611a60637bdacc - () https://git.kernel.org/stable/c/0fb7aa04c19eac4417f360a9f7611a60637bdacc - Patch
References () https://git.kernel.org/stable/c/30e8aee77899173a82ae5ed89f536c096f20aaeb - () https://git.kernel.org/stable/c/30e8aee77899173a82ae5ed89f536c096f20aaeb - Patch
References () https://git.kernel.org/stable/c/3561442599804905c3defca241787cd4546e99a7 - () https://git.kernel.org/stable/c/3561442599804905c3defca241787cd4546e99a7 - Patch
References () https://git.kernel.org/stable/c/5a515d13e15536e82c5c7c83eb6cf5bc4827fee5 - () https://git.kernel.org/stable/c/5a515d13e15536e82c5c7c83eb6cf5bc4827fee5 - Patch
References () https://git.kernel.org/stable/c/7f1564b2b2072b7aa1ac75350e9560a07c7a44fd - () https://git.kernel.org/stable/c/7f1564b2b2072b7aa1ac75350e9560a07c7a44fd - Patch
References () https://git.kernel.org/stable/c/b33a534610067ade2bdaf2052900aaad99701353 - () https://git.kernel.org/stable/c/b33a534610067ade2bdaf2052900aaad99701353 - Patch
References () https://git.kernel.org/stable/c/b6c72479748b7ea09f53ed64b223cee6463dc278 - () https://git.kernel.org/stable/c/b6c72479748b7ea09f53ed64b223cee6463dc278 - Patch
References () https://git.kernel.org/stable/c/fa40ebef69234e39ec2d26930d045f2fb9a8cb2b - () https://git.kernel.org/stable/c/fa40ebef69234e39ec2d26930d045f2fb9a8cb2b - Patch

01 Apr 2025, 16:15

Type Values Removed Values Added
New CVE
Information

Published : 2025-04-01 16:15

Updated : 2025-04-11 13:13

NVD link : CVE-2025-21920

Mitre link : CVE-2025-21920

CVE.ORG link : CVE-2025-21920

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-125

Out-of-bounds Read