CVE-2026-74668
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.
How to fix
- Linux Linux9c7e8ff48c377bef18c3d178748aea0575b69ede, 2a73b2c37ee3060a880b53cd24783d93fc7be5f8, e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2, d85d2fd54e901637c81d847811e03c662aee13cd, 016763e829cac37b3234eace86fd0a4c560de4a7, 27e068d1b35dbec10a3cf268887c94407be4badc, d48ea5c9c4c34dc0df621f0e39ed3a16b644621a, 21b5953e7494c16a42e6cd8cf110e18d13ae4a6b or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < 9c7e8ff48c377bef18c3d178748aea0575b69ede, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < 2a73b2c37ee3060a880b53cd24783d93fc7be5f8, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < d85d2fd54e901637c81d847811e03c662aee13cd, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < 016763e829cac37b3234eace86fd0a4c560de4a7, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < 27e068d1b35dbec10a3cf268887c94407be4badc, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < d48ea5c9c4c34dc0df621f0e39ed3a16b644621a, 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1 ≤ v < 21b5953e7494c16a42e6cd8cf110e18d13ae4a6b, 2.6.31 | 9c7e8ff48c377bef18c3d178748aea0575b69ede, 2a73b2c37ee3060a880b53cd24783d93fc7be5f8, e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2, d85d2fd54e901637c81d847811e03c662aee13cd, 016763e829cac37b3234eace86fd0a4c560de4a7, 27e068d1b35dbec10a3cf268887c94407be4badc, d48ea5c9c4c34dc0df621f0e39ed3a16b644621a, 21b5953e7494c16a42e6cd8cf110e18d13ae4a6b |
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