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CVE-2026-74668

Unknown

Last modified

CVE-2026-74668 is a vulnerability of currently unknown severity. 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.

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.

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1, < d85d2fd54e901637c81d847811e03c662aee13cd; >= 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1, < 016763e829cac37b3234eace86fd0a4c560de4a7; >= 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1, < 27e068d1b35dbec10a3cf268887c94407be4badc; >= 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1, < d48ea5c9c4c34dc0df621f0e39ed3a16b644621a; >= 69e3c75f4d541a6eb151b3ef91f34033cb3ad6e1, < 21b5953e7494c16a42e6cd8cf110e18d13ae4a6b
LinuxLinux2.6.31

References

Timeline

Published
Last Modified
Status
Received

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.
How severe is CVE-2026-74668?
Severity scoring for CVE-2026-74668 is pending analysis.
How do I fix CVE-2026-74668?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST