CVE-2025-39947: Linux kernel · net/mlx5e: Harden uplink netdev access against device unbind
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d1f3db4e7a3be29fc17f01850f162363f919370d : update Linux kernel when convenient.
Data as of 5 Nov 2026, 23:23 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- 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, 2026-11-05.
- Patch
- Available – fixed in d1f3db4e7a3be29fc17f01850f162363f919370d, 8df354eb2dd63d111ed5ae2e956e0dbb22bcf93b, 6b4be64fd9fec16418f365c2d8e47a7566e9eba5 +1
Exploitation evidence
Disclosed: evidence found.
CVE published 4 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 5 Nov 2026.
What to do
Upgrade Linux kernel to d1f3db4e7a3be29fc17f01850f162363f919370d, 8df354eb2dd63d111ed5ae2e956e0dbb22bcf93b, 6b4be64fd9fec16418f365c2d8e47a7566e9eba5 or 2cb17c88edd3a1c7aa6bc880dcdb35a6866fcb2e.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
Description
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.
References
- git.kernel.org/stable/c/2cb17c88edd3a1c7aa6bc880dcdb35a6866fcb2e (opens in a new tab)
- git.kernel.org/stable/c/d1f3db4e7a3be29fc17f01850f162363f919370d (opens in a new tab)
- git.kernel.org/stable/c/8df354eb2dd63d111ed5ae2e956e0dbb22bcf93b (opens in a new tab)
- git.kernel.org/stable/c/6b4be64fd9fec16418f365c2d8e47a7566e9eba5 (opens in a new tab)