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CVE Record

CVE-2025-39947: net/mlx5e: Harden uplink netdev access against device unbind

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Harden uplink netdev access against device unbind The function mlx5_uplink_netdev_get() gets the uplink netdevice pointer from mdev->mlx5e_res.uplink_netdev. However, the netdevice can be removed and its pointer cleared when unbound from the mlx5_core.eth driver. This results in a NULL pointer, causing a kernel panic. BUG: unable to handle page fault for address: 0000000000001300 at RIP: 0010:mlx5e_vport_rep_load+0x22a/0x270 [mlx5_core] Call Trace: <TASK> mlx5_esw_offloads_rep_load+0x68/0xe0 [mlx5_core] esw_offloads_enable+0x593/0x910 [mlx5_core] mlx5_eswitch_enable_locked+0x341/0x420 [mlx5_core] mlx5_devlink_eswitch_mode_set+0x17e/0x3a0 [mlx5_core] devlink_nl_eswitch_set_doit+0x60/0xd0 genl_family_rcv_msg_doit+0xe0/0x130 genl_rcv_msg+0x183/0x290 netlink_rcv_skb+0x4b/0xf0 genl_rcv+0x24/0x40 netlink_unicast+0x255/0x380 netlink_sendmsg+0x1f3/0x420 __sock_sendmsg+0x38/0x60 __sys_sendto+0x119/0x180 do_syscall_64+0x53/0x1d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Ensure the pointer is valid before use by checking it for NULL. If it is valid, immediately call netdev_hold() to take a reference, and preventing the netdevice from being freed while it is in use.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw can crash a host when the mlx5 Ethernet driver uses an uplink network-device pointer after device unbind clears it. The documented impact is kernel panic, so business risk is service interruption on affected Linux systems using this driver path.

Executive priority

Patch during the next normal Linux maintenance window, faster for production hosts relying on mlx5 networking. The known impact is host crash, not confirmed data compromise or active exploitation.

Technical view

mlx5_uplink_netdev_get() reads mdev->mlx5e_res.uplink_netdev, but unbinding from mlx5_core.eth can clear the pointer. Later mlx5e_vport_rep_load() may dereference NULL during eswitch/devlink mode handling. The fix validates the pointer, then immediately takes a netdev reference with netdev_hold().

Likely exposure

Exposure appears limited to Linux systems with mlx5e/mlx5_core networking in use, especially environments using eswitch offloads or devlink eswitch mode operations. The bundle lists Linux kernel affected versions and stable fixes, but gives no CVSS score.

Exploitation context

The source shows a kernel panic path and no evidence of public exploitation. KEV is false in the bundle. Treat this as a local or operational denial-of-service risk unless vendor advisories provide broader exploitability details.

Researcher notes

The evidence supports a NULL-pointer dereference caused by a stale or cleared uplink netdev pointer after unbind. The public bundle does not include CVSS, CWE, exploit status, or full downstream distribution impact.

Mitigation direction

  • Apply the relevant Linux stable kernel fix or distribution kernel update.
  • Prioritize hosts using mlx5e/mlx5_core networking or eswitch offloads.
  • Check vendor kernel advisories for exact affected package versions.
  • Avoid unnecessary driver unbind or eswitch mode changes on exposed production hosts until patched.

Validation and detection

  • Inventory kernels and confirm whether mlx5_core or mlx5e is loaded.
  • Identify hosts using devlink eswitch mode or representor networking.
  • Compare installed kernel builds against distribution advisories and stable fix availability.
  • Review kernel logs for mlx5e_vport_rep_load or mlx5_eswitch panic traces.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux7a9fb35e8c3a67145fca262c304de65cb2f83abf, 7a9fb35e8c3a67145fca262c304de65cb2f83abf, 7a9fb35e8c3a67145fca262c304de65cb2f83abf, 7a9fb35e8c3a67145fca262c304de65cb2f83abfunaffected
LinuxLinux5.13, 0, 6.6.108, 6.12.49, 6.16.9, 6.17affected
Weakness

CWE details

No CWE listed

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