In the Linux kernel, the following vulnerability has been resolved:
net/sched: fix netdevice reference leaks in attach_default_qdiscs()
In attach_default_qdiscs(), if a dev has multiple queues and queue 0 fails to attach qdisc because there is no memory in attach_one_default_qdisc(). Then dev->qdisc will be noop_qdisc by default. But the other queues may be able to successfully attach to default qdisc.
In this case, the fallback to noqueue process will be triggered. If the original attached qdisc is not released and a new one is directly attached, this will cause netdevice reference leaks.
The following is the bug log:
veth0: default qdisc (fq_codel) fail, fallback to noqueue unregister_netdevice: waiting for veth0 to become free. Usage count = 32 leaked reference. qdisc_alloc+0x12e/0x210 qdisc_create_dflt+0x62/0x140 attach_one_default_qdisc.constprop.41+0x44/0x70 dev_activate+0x128/0x290 __dev_open+0x12a/0x190 __dev_change_flags+0x1a2/0x1f0 dev_change_flags+0x23/0x60 do_setlink+0x332/0x1150 __rtnl_newlink+0x52f/0x8e0 rtnl_newlink+0x43/0x70 rtnetlink_rcv_msg+0x140/0x3b0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1bb/0x290 netlink_sendmsg+0x37c/0x4e0 sock_sendmsg+0x5f/0x70 ____sys_sendmsg+0x208/0x280
Fix this bug by clearing any non-noop qdiscs that may have been assigned before trying to re-attach.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-tools-debuginfoUpgrade python-perf-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernelUpgrade bpftoolUpgrade python-perfUpgrade kernel-livepatch-5.10.144-127.601Upgrade bpftool-debuginfoUpgrade kernel-livepatch-5.15.69-37.134Upgrade kernel-headersUpgrade perfUpgrade kernel-debuginfoUpgrade kernel-toolsUpgrade kernel-tools-develUpgrade kernel-develUpgrade kernel-debuginfo-common-aarch64Upgrade perf-debuginfo | May 20, 2026 | May 20, 2026 |
| Debian | — | Upgrade linux | Jun 20, 2025 | Jun 20, 2025 |
| Dell Powerstore Dsa2025429 | — | Upgrade Dell PowerStoreOS to the latest version | Dec 3, 2025 | Dec 2, 2025 |
| Dell Powerstore Dsa2026039 | — | Upgrade Dell PowerStoreOS to the latest version | Jan 13, 2026 | Jan 6, 2026 |
| Huawei Euleros 2_0_sp13 | — | Upgrade bpftoolUpgrade kernel-toolsUpgrade kernelUpgrade kernel-abi-stablelistsUpgrade python3-perfUpgrade kernel-tools-libs | Feb 3, 2026 | Feb 2, 2026 |
| Redhat_linux | — | No solution exists | Jul 9, 2025 | Jun 18, 2025 |
| Ubuntu | — | Upgrade linux-raspiUpgrade linux-hwe-5.15Upgrade linux-lowlatencyUpgrade linux-aws-5.15Upgrade linux-azureUpgrade linux-awsUpgrade linuxUpgrade linux-gcpUpgrade linux-intel-iotg-5.15Upgrade linux-azure-5.15Upgrade linux-realtimeUpgrade linux-kvmUpgrade linux-lowlatency-hwe-5.15Upgrade linux-gkeUpgrade linux-intel-iotgUpgrade linux-oracle-5.15Upgrade linux-gcp-5.15Upgrade linux-riscv-5.15Upgrade linux-nvidiaUpgrade linux-gkeopUpgrade linux-ibmUpgrade linux-oracle | Jun 26, 2025 | Jun 18, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | May 27, 2026 | Jun 18, 2025 |
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