cbcvebase.
CVE-2025-37864
published 2025-05-09

CVE-2025-37864: In the Linux kernel, the following vulnerability has been resolved: net: dsa: clean up FDB, MDB, VLAN entries on unbind As explained in many places such as…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.26%
17.4th percentile
In the Linux kernel, the following vulnerability has been resolved: net: dsa: clean up FDB, MDB, VLAN entries on unbind As explained in many places such as commit b117e1e8a86d ("net: dsa: delete dsa_legacy_fdb_add and dsa_legacy_fdb_del"), DSA is written given the assumption that higher layers have balanced additions/deletions. As such, it only makes sense to be extremely vocal when those assumptions are violated and the driver unbinds with entries still present. But Ido Schimmel points out a very simple situation where that is wrong: https://lore.kernel.org/netdev/ZDazSM5UsPPjQuKr@shredder/ (also briefly discussed by me in the aforementioned commit). Basically, while the bridge bypass operations are not something that DSA explicitly documents, and for the majority of DSA drivers this API simply causes them to go to promiscuous mode, that isn't the case for all drivers. Some have the necessary requirements for bridge bypass operations to do something useful - see dsa_switch_supports_uc_filtering(). Although in tools/testing/selftests/net/forwarding/local_termination.sh, we made an effort to popularize better mechanisms to manage address filters on DSA interfaces from user space - namely macvlan for unicast, and setsockopt(IP_ADD_MEMBERSHIP) - through mtools - for multicast, the fact is that 'bridge fdb add ... self static local' also exists as kernel UAPI, and might be useful to someone, even if only for a quick hack. It seems counter-productive to block that path by implementing shim .ndo_fdb_add and .ndo_fdb_del operations which just return -EOPNOTSUPP in order to prevent the ndo_dflt_fdb_add() and ndo_dflt_fdb_del() from running, although we could do that. Accepting that cleanup is necessary seems to be the only option. Especially since we appear to be coming back at this from a different angle as well. Russell King is noticing that the WARN_ON() triggers even for VLANs: https://lore.kernel.org/netdev/[email protected]/ What happens i

Affected

26 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.25-1 (forky)linux 6.12.25-1 (forky)
linuxlinux
linuxlinux>= 0832cd9f1f023226527e95002d537123061ddac4 < 5e531e71b9d21d5e985251440e0d722f71299b7a5e531e71b9d21d5e985251440e0d722f71299b7a
linuxlinux>= 0832cd9f1f023226527e95002d537123061ddac4 < 86c6613a69bca815f1865ed8cedfd4b9142621ab86c6613a69bca815f1865ed8cedfd4b9142621ab
linuxlinux>= 0832cd9f1f023226527e95002d537123061ddac4 < 8fcc1e6f808912977caf17366c625b95dc29ba4f8fcc1e6f808912977caf17366c625b95dc29ba4f
linuxlinux>= 0832cd9f1f023226527e95002d537123061ddac4 < 99c50c98803425378e08a7394dc885506dc85f0699c50c98803425378e08a7394dc885506dc85f06
linuxlinux>= 0832cd9f1f023226527e95002d537123061ddac4 < 7afb5fb42d4950f33af2732b8147c552659f79b77afb5fb42d4950f33af2732b8147c552659f79b7
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.25-16.12.25-1
linuxlinux_kernel>= 0 < 6.12.25-16.12.25-1
linuxlinux_kernel>= 0 < 6.8.0-100.1006.8.0-100.100
linuxlinux_kernel>= 0 < 6.14.0-22.226.14.0-22.22
linuxlinux_kernel>= 5.18 < 6.6.886.6.88
linuxlinux_kernel>= 6.13 < 6.14.46.14.4
linuxlinux_kernel>= 6.7 < 6.12.256.12.25
msrcazl3_kernel_6.6.85.1-4_on_azure_linux_3.0
msrcazl3_kernel_6.6.92.2-1_on_azure_linux_3.0
ubuntulinux-aws
ubuntulinux-aws-6.8
ubuntulinux-gkeop
ubuntulinux-nvidia
ubuntulinux-nvidia-6.8
ubuntulinux-oracle
ubuntulinux-oracle-6.8
ubuntulinux-raspi-realtime

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_msrc5.5MEDIUM
vendor_redhat5.5MEDIUM
vendor_ubuntu3.2LOW
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