CVE-2026-74668

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.

CVSS 3.1

7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.1% chance of exploitation in the next 30 days; higher than 2% of CVEs (scores of 2026-10-25)

Published

2026-08-22

Modified

2026-10-16

Record from

the NVD, synced 2026-10-19

References

• https://git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7
• https://git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b
• https://git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc
• https://git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8
• https://git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede

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