In the Linux kernel, the following vulnerability has been resolved: macvlan: fix...
🔗 CVE IDs covered (1)
📋 Description
In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix macvlan_get_size() not reserving space for IFLA_MACVLAN_BC_CUTOFF
macvlan_get_size() does not account for IFLA_MACVLAN_BC_CUTOFF, but macvlan_fill_info() conditionally includes it when port->bc_cutoff != 1. This causes nla_put_s32() to fail with -EMSGSIZE when the netlink skb runs out of space, triggering a WARN_ON in rtnetlink and preventing the interface from being dumped.
The bug can be reproduced with:
ip link add macvlan0 link eth0 type macvlan mode bridge ip link set macvlan0 type macvlan bc_cutoff 0 ip -d link show macvlan0 # fails with -EMSGSIZE
The bc_cutoff feature was added in commit 954d1fa1ac93 ("macvlan: Add netlink attribute for broadcast cutoff"), which added the nla_put_s32() call in macvlan_fill_info() but missed adding the corresponding nla_total_size(4) in macvlan_get_size(). A follow-up commit 55cef78c244d ("macvlan: add forgotten nla_policy for IFLA_MACVLAN_BC_CUTOFF") fixed the missing nla_policy entry but still did not fix the size calculation.
🔗 References (7)
- https://nvd.nist.gov/vuln/detail/CVE-2026-53013
- https://git.kernel.org/stable/c/1c004f14ccdc11585625c168bb9a7c5e1b8afb0c
- https://git.kernel.org/stable/c/4979252758387b338ca968ba7e0515b0ae2257e3
- https://git.kernel.org/stable/c/77ecfa4e27f282d224215895ddfbeb916fc75e24
- https://git.kernel.org/stable/c/b6b7154e9f5d75b608ceb2d05b376de8c638c40e
- https://git.kernel.org/stable/c/fa92a77b0ed4d5f11a71665a232ac5a54a4b055d
- https://github.com/advisories/GHSA-mh75-v23p-mcvc