CVE-2026-74668 (CVSS 7.8)

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.

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CVSS v3.1 Score

7.8

HIGH

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

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other 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 https://git.kernel.org/stable/c/d48ea5c9c4c34dc0df621f0e39ed3a16b644621a https://git.kernel.org/stable/c/d85d2fd54e901637c81d847811e03c662aee13cd https://git.kernel.org/stable/c/e79f59a8527a49078cfaf8fe8fb5fcefc20c76d2

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-74668? +

CVE-2026-74668 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-74668? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-74668