CVE-2026-45952 PUBLISHED

eth: fbnic: Add validation for MTU changes

Assigner: Linux
Reserved: 13.05.2026 Published: 27.05.2026 Updated: 27.05.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 1b0a3950dbd4fa278dc33401a4faba2a23307a16 to d7eaa006c0444a5d4671be7efe6dbb33ef8b515e (excl.)
  • affected from 1b0a3950dbd4fa278dc33401a4faba2a23307a16 to 03399063aa0c67fd8bdfd69467ddb849bb3b97df (excl.)
  • affected from 1b0a3950dbd4fa278dc33401a4faba2a23307a16 to ccd8e87748ad083047d6c8544c5809b7f96cc8df (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.18 is affected
  • unaffected from 0 to 6.18 (excl.)
  • unaffected from 6.18.14 to 6.18.* (incl.)
  • unaffected from 6.19.4 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References