CVE-2026-45952
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
A vulnerability related to MTU change validation in the fbnic driver has been resolved in the Linux kernel. Increasing the MTU beyond the HDS threshold causes packet fragmentation, which may lead to issues with TCP data transmission.
Risk Assessment
Organizations may encounter problems with new TCP stream transmissions, potentially resulting in data loss or reduced network performance.
Recommendation
It is recommended to monitor MTU settings and avoid increasing them after attaching an XDP program to prevent packet fragmentation issues.
Original NVD description (English source)
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.