CVE-2026-74744
Received Received - Intake

Buffer Overflow in Linux Kernel IPvLAN

Publication date: 2026-08-26

Last updated on: 2026-08-26

Assigner: kernel.org

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.

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Meta Information

Published
2026-08-26
Last Modified
2026-08-26
Generated
2026-08-26
AI Q&A
2026-08-26
EPSS Evaluated
N/A
NVD
CVE-2026-74744
EUVD
EUVD-2026-66574

Affected Vendors & Products

Currently, no data is known.

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves ipvlan devices not properly inheriting needed headroom and tailroom from the physical device during initialization. This can cause issues when the underlying device requires extra space for headers or trailers, leading to packet handling problems or crashes.

Detection Guidance

This vulnerability may cause network packet issues or crashes. Check kernel logs for KASAN slab-use-after-free errors or skb headroom underflows. Use commands like dmesg | grep -i kasan or dmesg | grep -i headroom to detect anomalies.

Impact Analysis

The vulnerability may cause reallocation overhead, skb headroom underflows, or crashes like KASAN slab-use-after-free when handling packets. This affects network performance and stability, especially if using macsec, ipsec, wireguard, tunnels, or veth with rx headroom.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for CVE-2026-74744. Monitor network interfaces for errors and ensure ipvlan devices are properly configured with sufficient headroom and tailroom.

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