In the Linux kernel, the following vulnerability has been resolved: eth: fbnic: Add validation for MTU changes Increasing the MTU beyond the HDS threshold causes the hardware to fragment packets across multiple buffers. If a single-buffer XDP program is attached, the driver will drop all multi-frag frames. While we can't prevent a remote sender from sending non-TCP packets larger than the MTU, this will prevent users from inadvertently breaking new TCP streams. Traditionally, drivers supported XDP with MTU less than 4Kb (packet per page). Fbnic currently prevents attaching XDP when MTU is too high. But it does not prevent increasing MTU after XDP is attached.

A flaw was found in the Linux kernel's fbnic driver. This vulnerability allows a local user to cause a Denial of Service (DoS) by increasing the Maximum Transmission Unit (MTU) beyond the hardware's threshold while an eXpress Data Path (XDP) program is attached. This improper validation of MTU changes leads to the driver dropping all multi-fragmented network frames, effectively breaking new TCP connections.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-45952 https://nvd.nist.gov/vuln/detail/CVE-2026-45952 https://lore.kernel.org/linux-cve-announce/2026052731-CVE-2026-45952-8392@gregkh/T