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.
References8
- git.kernel.org/stable/c/016763e829cac37b3234eace86fd0a4c560de4a7
- git.kernel.org/stable/c/21b5953e7494c16a42e6cd8cf110e18d13ae4a6b
- git.kernel.org/stable/c/27e068d1b35dbec10a3cf268887c94407be4badc
- git.kernel.org/stable/c/2a73b2c37ee3060a880b53cd24783d93fc7be5f8
- git.kernel.org/stable/c/9c7e8ff48c377bef18c3d178748aea0575b69ede
- git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a
- git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd
- git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 3 · as of 9 November 2026
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.