CVE-2025-39947

Kernel panic via unheld mlx5e uplink pointer

Published Oct 4, 2025 · Updated Oct 4, 2025

NULL pointer dereference in affected Linux kernel versions allows local users to crash the kernel through mlx5e eswitch reconfiguration. mlx5_uplink_netdev_get reads mdev->mlx5e_res.uplink_netdev without first validating the pointer and holding a netdevice reference against concurrent removal. Exploitation requires low-privileged local access and an mlx5 eswitch path that uses the uplink after mlx5_core.eth device unbind.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in affected Linux kernel versions allows local users to crash the kernel through mlx5e eswitch reconfiguration. mlx5_uplink_netdev_get reads mdev->mlx5e_res.uplink_netdev without first validating the pointer and holding a netdevice reference against concurrent removal. Exploitation requires low-privileged local access and an mlx5 eswitch path that uses the uplink after mlx5_core.eth device unbind.

The record

CVE
CVE-2025-39947
Published
Oct 4, 2025
Updated
Oct 4, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.13
  2. Affected versionversion=7a9fb35e8c3a67145fca262c304de65cb2f83abf <2cb17c88edd3a1c7aa6bc880dcdb35a6866fcb2e
  3. Affected versionversion=7a9fb35e8c3a67145fca262c304de65cb2f83abf <6b4be64fd9fec16418f365c2d8e47a7566e9eba5
  4. Affected versionversion=7a9fb35e8c3a67145fca262c304de65cb2f83abf <8df354eb2dd63d111ed5ae2e956e0dbb22bcf93b
  5. Affected versionversion=7a9fb35e8c3a67145fca262c304de65cb2f83abf <d1f3db4e7a3be29fc17f01850f162363f919370d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=7a9fb35e8c3a67145fca262c304de65cb2f83abf <2cb17c88edd3a1c7aa6bc880dcdb35a6866fcb2e; version=7a9fb35e8c3a67145fca262c304de65cb2f83abf <6b4be64fd9fec16418f365c2d8e47a7566e9eba5; version=7a9fb35e8c3a67145fca262c304de65cb2f83abf <8df354eb2dd63d111ed5ae2e956e0dbb22bcf93b; version=7a9fb35e8c3a67145fca262c304de65cb2f83abf <d1f3db4e7a3be29fc17f01850f162363f919370d

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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