CVE-2026-45952 Details
Description
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 vulnerability exists in the Linux kernel's fbnic driver related to how it handles changes to the Maximum Transmission Unit (MTU) size. When the MTU is increased beyond a certain threshold, the hardware fragments packets across multiple buffers. This can cause issues if a single-buffer eBPF program is attached, as the driver will drop all fragmented frames. Although it's not possible to prevent a remote sender from sending non-TCP packets larger than the MTU, this vulnerability can disrupt new TCP streams. The fbnic driver currently allows XDP programs to be attached when the MTU is too high, but does not prevent the MTU from being increased afterwards.
The vulnerability has been addressed in the Linux kernel. Users should upgrade to the latest version.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/03399063aa0c67fd8bdfd69467ddb849bb3b97df | kernel.org | Patch |
| https://git.kernel.org/stable/c/ccd8e87748ad083047d6c8544c5809b7f96cc8df | kernel.org | Patch |
| https://git.kernel.org/stable/c/d7eaa006c0444a5d4671be7efe6dbb33ef8b515e | kernel.org | Patch |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-noinfo | Insufficient Information to Classify Weakness | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.18, < 6.18.14 >= 6.19, < 6.19.4 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| Jun 16, 2026 | Initial Analysis | [email protected] |
| May 27, 2026 | New CVE Received | kernel.org |