cbcvebase.
CVE-2025-21920
published 2025-04-01

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…

PriorityP432high7.1CVSS 3.1
AVLACLPRLUINSUCHINAH
EPSS
0.21%
11.1th percentile
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.

Affected

30 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.133-1 (bookworm)linux 6.1.133-1 (bookworm)
debianlinux-6.1< linux 6.1.133-1 (bookworm)linux 6.1.133-1 (bookworm)
linuxlinux
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < 7f1564b2b2072b7aa1ac75350e9560a07c7a44fd7f1564b2b2072b7aa1ac75350e9560a07c7a44fd
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < fa40ebef69234e39ec2d26930d045f2fb9a8cb2bfa40ebef69234e39ec2d26930d045f2fb9a8cb2b
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < 0fb7aa04c19eac4417f360a9f7611a60637bdacc0fb7aa04c19eac4417f360a9f7611a60637bdacc
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < 5a515d13e15536e82c5c7c83eb6cf5bc4827fee55a515d13e15536e82c5c7c83eb6cf5bc4827fee5
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < 3561442599804905c3defca241787cd4546e99a73561442599804905c3defca241787cd4546e99a7
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < 30e8aee77899173a82ae5ed89f536c096f20aaeb30e8aee77899173a82ae5ed89f536c096f20aaeb
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < b6c72479748b7ea09f53ed64b223cee6463dc278b6c72479748b7ea09f53ed64b223cee6463dc278
linuxlinux>= 22bedad3ce112d5ca1eaf043d4990fa2ed698c87 < b33a534610067ade2bdaf2052900aaad99701353b33a534610067ade2bdaf2052900aaad99701353
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.237-15.10.237-1
linuxlinux_kernel>= 0 < 6.1.133-16.1.133-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 6.12.19-16.12.19-1
linuxlinux_kernel>= 0 < 5.4.0-216.2365.4.0-216.236
linuxlinux_kernel>= 0 < 5.15.0-140.1505.15.0-140.150
linuxlinux_kernel>= 0 < 6.8.0-84.846.8.0-84.84
linuxlinux_kernel>= 2.6.35 < 5.4.2915.4.291
linuxlinux_kernel>= 5.11 < 5.15.1795.15.179
linuxlinux_kernel>= 5.16 < 6.1.1316.1.131
linuxlinux_kernel>= 5.5 < 5.10.2355.10.235
linuxlinux_kernel>= 6.13 < 6.13.76.13.7
linuxlinux_kernel>= 6.2 < 6.6.836.6.83

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.1HIGH
vendor_msrc7.1HIGH
vendor_redhat7.1HIGH
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