# CVE-2026-45952: linux: In the Linux kernel, the following vulnerability has been resolved:  eth: fbnic: Add validation for MTU changes  Incr...

CVE-2026-45952 is fixed in linux on 1 platform by DEBIAN-CVE-2026-45952 (version 6.18.14-1), released May 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-45952
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 27, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.14-1 | [DEBIAN-CVE-2026-45952](https://patchblox.com/security/data/fix/linux/debian-cve-2026-45952.md) | May 27, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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