Linux Kernel up to 7.0.11/7.1-rc5 tap tap_get_user_xdp buffer overflow

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.0.11/7.1-rc5. It has been classified as critical. This impacts the function tap_get_user_xdp of the component tap. The manipulation leads to buffer overflow. This vulnerability is documented as CVE-2026-46320. There is not any exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.0.11/7.1-rc5. It has been rated as critical. This issue affects the function tap_get_user_xdp of the component tap. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: tap: free page on error paths in tap_get_user_xdp() tap_get_user_xdp() rejects a frame shorter than ETH_HLEN with -EINVAL, and returns -ENOMEM when build_skb() fails. Both paths jump to the err label without freeing the page that vhost_net_build_xdp() allocated for the frame. tap_sendmsg() discards the per-buffer return value and always returns 0, so vhost_tx_batch() takes the success path and never frees the page; each rejected frame in a batch leaks one page-frag chunk. Free the page on both error paths, before the skb is built. This is the tap counterpart of the same leak in tun_xdp_one().

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-46320 since 05/13/2026. The exploitation is known to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/10/2026).

Upgrading to version 7.0.12 or 7.1-rc6 eliminates this vulnerability. Applying the patch 18a84c35842e19cd3c5534d8cee73d31863f696d/3bcf7aec6a9d16438f2cec29f5d7c8d5b8edf9b2 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1870). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9
• 7.0.10
• 7.0.11
• 7.1-rc1
• 7.1-rc2
• 7.1-rc3
• 7.1-rc4
• 7.1-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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