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VulnerabilityPublished Updated

CVE-2026-43012: Linux kernel · net/mlx5: Fix switchdev mode rollback in case of failure

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in e27153b2bd6e6699b544ac4dfa35d167bed5e642 : patch Linux kernel soon.

Data as of 6 Nov 2026, 16:33 UTC

Severity
High

Rated High by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch
Available – fixed in e27153b2bd6e6699b544ac4dfa35d167bed5e642, 4363698838b7ec6e8d85b179495889aa7e522f91, 403186400a1a6166efe7031edc549c15fee4723f +2

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 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

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=6.12.9 <6.12.81
Fixed in
  • e27153b2bd6e6699b544ac4dfa35d167bed5e642
  • 4363698838b7ec6e8d85b179495889aa7e522f91
  • 403186400a1a6166efe7031edc549c15fee4723f
  • 6.12.81
  • 2ebb13f3e8be0b61f72425b34cce60c8b6ad1891
LinuxLinuxAffected
  • =6.13
Fixed in–

AI-suggested

A patch is available and has been applied in Linux kernel version 6.12.81 and later. Users should upgrade to version 6.12.81 or later to remediate this issue. Since this is a kernel-level fix, applying the official kernel update is the recommended mitigation. The vendor manages remediation for this cloud-hosted service; check the vendor advisory for confirmation if using a cloud service.

Description

CVE-2026-43012 is a vulnerability in the Linux kernel's mlx5 network driver related to switchdev mode rollback. Prior to the fix, if switchdev mode failed internally, the rollback to legacy mode would unregister the uplink network device and leave it unregistered, causing a kernel bug and system crash. The patch prevents unregistering the netdev by setting a rollback flag to indicate legacy mode, avoiding the kernel bug.

References

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