CVE-2026-74668
🔶 mediumSummary
In the Linux kernel, the following vulnerability has been resolved: packet: use consistent hard_header_len in TX_RING send path tpacket_snd() reads dev->hard_header_len independently for skb allocation and header construction in tpacket_fill_skb(). Concurrent netdevice reconfiguration can therefore make the reserved headroom smaller than the amount later pushed, or make copylen - hard_header_len negative. Snapshot hard_header_len once before processing ring frames and use it for the frame lim
Description
In the Linux kernel, the following vulnerability has been resolved:
packet: use consistent hard_header_len in TX_RING send path
tpacket_snd() reads dev->hard_header_len independently for skb
allocation and header construction in tpacket_fill_skb(). Concurrent
netdevice reconfiguration can therefore make the reserved headroom
smaller than the amount later pushed, or make copylen - hard_header_len
negative.
Snapshot hard_header_len once before processing ring frames and use it
for the frame limit, headroom allocation, copy length, and skb
construction. Pass the snapshot to tpacket_fill_skb().
The separate SOCK_DGRAM consistency problem between hard_header_len and
header_ops->create is not addressed here.