CVE-2026-74744

ipvlan: inherit needed_headroom and needed_tailroom from phy_dev

State: Published
Severity: 9.8 Critical
Published: Aug 26, 2026
Updated: Oct 16, 2026
Reserved: Aug 15, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

ipvlan: inherit needed_headroom and needed_tailroom from phy_dev

ipvlan devices inherit hard_header_len from phy_dev during ipvlan_init(), but leave needed_headroom and needed_tailroom set to 0.

When the underlying phy_dev (or stacked lower device) requires extra headroom or tailroom for headers/trailers (e.g. macsec, ipsec, wireguard, tunnels, or veth with rx headroom), upper layers calculating packet headroom and tailroom fail to reserve sufficient space.

This can result in reallocation overhead, skb headroom underflows, or KASAN slab-use-after-free crashes when dev_hard_header() / ipvlan_hard_header() prepends header data or when lower devices append tailroom.

Fix this by: 1. Inheriting needed_headroom and needed_tailroom from phy_dev in ipvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached ipvlans in ipvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	2ad7bf3638411cb547f2823df08166c13ab04269 to before af602c4d0ee548da18e2409b4b4da1079625a372Affected 2ad7bf3638411cb547f2823df08166c13ab04269 to before f3c17ff65f54781cde696e16a6c577615ed735aaAffected 2ad7bf3638411cb547f2823df08166c13ab04269 to before c0fbe31f6b20ade0465130685859faa5c86fda59Affected 2ad7bf3638411cb547f2823df08166c13ab04269 to before 5f33188457bbcc1b11ca87084037963c516ed3d9Affected 2ad7bf3638411cb547f2823df08166c13ab04269 to before 5c2ca77212eb38559b0353b8363b7a84f4b019ddAffected 2ad7bf3638411cb547f2823df08166c13ab04269 to before e16e960d55a40d36bd7c2494cc005e757dc9a1efAffected
LinuxLinux	3.19Affected before 3.19Not affected 6.1.184 through 6.1.Not affected 6.6.153 through 6.6.Not affected 6.12.105 through 6.12.Not affected 6.18.46 through 6.18.Not affected 7.1.10 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

2ad7bf3638411cb547f2823df08166c13ab04269 to before af602c4d0ee548da18e2409b4b4da1079625a372Affected
2ad7bf3638411cb547f2823df08166c13ab04269 to before f3c17ff65f54781cde696e16a6c577615ed735aaAffected
2ad7bf3638411cb547f2823df08166c13ab04269 to before c0fbe31f6b20ade0465130685859faa5c86fda59Affected
2ad7bf3638411cb547f2823df08166c13ab04269 to before 5f33188457bbcc1b11ca87084037963c516ed3d9Affected
2ad7bf3638411cb547f2823df08166c13ab04269 to before 5c2ca77212eb38559b0353b8363b7a84f4b019ddAffected
2ad7bf3638411cb547f2823df08166c13ab04269 to before e16e960d55a40d36bd7c2494cc005e757dc9a1efAffected

LinuxLinux

3.19Affected
before 3.19Not affected
6.1.184 through 6.1.*Not affected
6.6.153 through 6.6.*Not affected
6.12.105 through 6.12.*Not affected
6.18.46 through 6.18.*Not affected
7.1.10 through 7.1.*Not affected
7.2 and laterNot affected

References

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