CVE-2026-74743
macvlan: inherit needed_headroom and needed_tailroom from lowerdev
Description
In the Linux kernel, the following vulnerability has been resolved: macvlan: inherit needed_headroom and needed_tailroom from lowerdev macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0. When the underlying lowerdev 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() / macvlan_hard_header() prepends header data or when lower devices append tailroom. Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events.
INFO
Published Date :
Aug. 26, 2026, 3:16 p.m.
Last Modified :
Aug. 26, 2026, 3:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2026-74743
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update the Linux kernel to the patched version.
- Ensure headroom and tailroom values are inherited.
- Propagate headroom/tailroom updates to attached macvlans.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-74743.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-74743 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-74743
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-74743 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74743 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 26, 2026
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: macvlan: inherit needed_headroom and needed_tailroom from lowerdev macvlan devices inherit hard_header_len from lowerdev during macvlan_init(), but leave needed_headroom and needed_tailroom set to 0. When the underlying lowerdev 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() / macvlan_hard_header() prepends header data or when lower devices append tailroom. Fix this by: 1. Inheriting needed_headroom and needed_tailroom from lowerdev in macvlan_init(). 2. Propagating needed_headroom and needed_tailroom updates to attached macvlans in macvlan_device_event() when receiving NETDEV_FEAT_CHANGE events. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/74xxx/CVE-2026-74743.json">CVE-2026-74743</a> Added Reference https://git.kernel.org/stable/c/28afc87bd8da0b3348bbbd834c8a89e83712cf5e Added Reference https://git.kernel.org/stable/c/8cd90e850e434577bf6774778657d26d6995e53f Added Reference https://git.kernel.org/stable/c/8f6a05dbac05725e0786701eb04778c5bdbe4eaa Added Reference https://git.kernel.org/stable/c/96fa90b74385b7f2b0d97251dd43d5ee6ca44668 Added Reference https://git.kernel.org/stable/c/bc9a00fb78e32bccc39d763bfd13a450705bac5d Added Reference https://git.kernel.org/stable/c/cef51860becd9700217c81732ca1eb1ea6ed6fe1