Bug 2481937 (CVE-2026-45952) - CVE-2026-45952 kernel: eth: fbnic: Add validation for MTU changes
Summary: CVE-2026-45952 kernel: eth: fbnic: Add validation for MTU changes
Keywords:
Status: NEW
Alias: CVE-2026-45952
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:03 UTC by OSIDB Bzimport
Modified: 2026-05-27 23:44 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-05-27 15:03:15 UTC
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.


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