CVE-2026-31728
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop A race condition between gether_disconnect() and eth_stop() leads to a NULL pointer dereference. Specifically, if eth_stop() is triggered concurrently while gether_disconnect() is tearing down the endpoints, eth_stop() attempts to access the cleared endpoint descriptor, causing the following NPE: Unable to handle kernel NULL pointer dereference Call trace: __dwc3_gadget_ep_enable+0x60/0x788 dwc3_gadget_ep_enable+0x70/0xe4 usb_ep_enable+0x60/0x15c eth_stop+0xb8/0x108 Because eth_stop() crashes while holding the dev->lock, the thread running gether_disconnect() fails to acquire the same lock and spins forever, resulting in a hardlockup: Core - Debugging Information for Hardlockup core(7) Call trace: queued_spin_lock_slowpath+0x94/0x488 _raw_spin_lock+0x64/0x6c gether_disconnect+0x19c/0x1e8 ncm_set_alt+0x68/0x1a0 composite_setup+0x6a0/0xc50 The root cause is that the clearing of dev->port_usb in gether_disconnect() is delayed until the end of the function. Move the clearing of dev->port_usb to the very beginning of gether_disconnect() while holding dev->lock. This cuts off the link immediately, ensuring eth_stop() will see dev->port_usb as NULL and safely bail out.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | forky | fixed | 6.19.12-1 |
| debian | sid | fixed | 6.19.12-1 |
| debian | trixie | fixed | 6.12.85-1 |
| debian | bullseye | fixed | 6.1.170-1~deb11u1 |
| linux-kernel | affected | 5.10.253 | |
| linux-kernel | 7.0 | affected | |
References
- https://git.kernel.org/stable/c/6ad77458637b78ec655e3da5f112c862e6690a9d
- https://git.kernel.org/stable/c/8ff689edfeceb5e3ec1623e09af2b2aa0f1098a8
- https://git.kernel.org/stable/c/a259ba0bce3b192c04334499690372a250f7d0b1
- https://git.kernel.org/stable/c/bbb09bb89ffa571475f66daca9482b974cd29d6a
- https://git.kernel.org/stable/c/e1e7a66584bf0aff3becb73c19fa31527889fc9e
- https://git.kernel.org/stable/c/e1eabb072c75681f78312c484ccfffb7430f206e
- https://git.kernel.org/stable/c/f02980594deef751e42133714aee25228f1494c6
- https://git.kernel.org/stable/c/f6813c2b2ae78def76b69e0f9d72f80e4a1c4aca
- https://www.suse.com/security/cve/CVE-2026-31728.html
- https://security-tracker.debian.org/tracker/CVE-2026-31728
CWEs
CWE-362
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.