SB2026082462 - Improper access control in Linux kernel xdp

Description

This security bulletin contains information about 1 vulnerability.

1) Improper access control (CVE-ID: CVE-2026-74709)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a local user to overwrite kernel-managed metadata.

The vulnerability exists due to improper access control in the xsk transmit metadata completion handling in AF_XDP when changing metadata flags after request processing. A local user can modify metadata flags after submission to cause the kernel to write a transmit timestamp that was not requested.

On the mlx5 multi-packet WQE path, metadata is evaluated per batch, which can affect descriptors in the same session beyond the first descriptor.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/0ba2e1eb07a826d021344e2f146b6716c58139eb
• https://git.kernel.org/stable/c/9f60a67df8d3c862503bee62bada8e7089cba438
• https://git.kernel.org/stable/c/eb4c613d4ebc3f664e70d572b8867ba114a8754e