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VulnerabilityPublished Updated

CVE-2026-45952: Linux kernel · eth: fbnic: Add validation for MTU changes

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 5.5 Medium.

Data as of 6 Nov 2026, 17:17 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1007.7~24.04.1 – 6.14.0-1018.18~24.04.1
11 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-gcp-6.11pkg:deb/ubuntu/linux-gcp-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1006.6~24.04.2 – 6.11.0-1017.17~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-gcp-6.14pkg:deb/ubuntu/linux-gcp-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1007.7~24.04.1 – 6.14.0-1021.22~24.04.1
11 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-hwe-6.11pkg:deb/ubuntu/linux-hwe-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-17.17~24.04.2 – 6.11.0-29.29~24.04.1
8 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-hwe-6.14pkg:deb/ubuntu/linux-hwe-6.14?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-24.24~24.04.3 – 6.14.0-37.37~24.04.1
10 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel fbnic driver to add validation for MTU changes after XDP attachment. Users should update to the patched kernel versions to prevent this issue. Since the vulnerability is addressed by this validation, no additional mitigation steps are necessary beyond applying the update.

Description

A vulnerability in the Linux kernel's fbnic driver related to MTU (Maximum Transmission Unit) changes has been addressed. The issue arises when the MTU is increased beyond the hardware's HDS threshold, causing packet fragmentation across multiple buffers. If a single-buffer XDP program is attached, the driver drops all multi-fragment frames. Previously, the driver prevented attaching XDP when the MTU was too high but did not prevent increasing the MTU after XDP was attached. This fix adds validation to prevent such MTU changes after XDP attachment.

References

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