In the Linux kernel, the following vulnerability has been resolved:
tun: zero the whole vnet header in tun_put_user()
tun_put_user() declares an on-stack struct virtio_net_hdr_v1_hash_tunnel without zeroing it. For a non-tunnel skb, virtio_net_hdr_tnl_from_skb() only initializes the first 10 bytes (sizeof(struct virtio_net_hdr)), leaving bytes 10..23 (num_buffers and the hash/tunnel fields) as stack garbage.
An unprivileged user can set the vnet header size to 24 with TUNSETVNETHDRSZ, so __tun_vnet_hdr_put() copies all 24 bytes of the partially-initialized struct to userspace, leaking 14 bytes of kernel stack on every read of a non-tunnel packet.
Fix it the same way tun_get_user() already does by zeroing the whole header right after declaration.
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_2023 | — | Upgrade kernel6.18-modules-extra-commonUpgrade kernel6.18-debuginfo-common-x86_64Upgrade kernel6.18-develUpgrade kernel6.18-tools-develUpgrade microvm-kernel6.18Upgrade kernel6.18Upgrade perf6.18Upgrade python3-perf6.18Upgrade bpftool6.18Upgrade kernel-livepatch-6.18.36-69.134Upgrade kernel6.18-debuginfoUpgrade bpftool6.18-debuginfoUpgrade kernel6.18-toolsUpgrade kernel6.18-debuginfo-common-aarch64Upgrade perf6.18-debuginfoUpgrade kernel6.18-tools-debuginfoUpgrade kernel6.18-modules-extraUpgrade python3-perf6.18-debuginfoUpgrade kernel6.18-headers | Jul 21, 2026 | Jun 24, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Jun 24, 2026 |
| Ubuntu | — | Upgrade linux-image-virtual-hwe-26.04Upgrade linux-image-7.0.0-1011-gcpUpgrade linux-image-7.0.0-1006-gkeUpgrade linux-image-gcpUpgrade linux-image-nvidia-bos-7.0Upgrade linux-image-7.0.0-1006-gke-64kUpgrade linux-image-7.0.0-31-genericUpgrade linux-image-7.0.0-1012-aws-64kUpgrade linux-image-gcp-7.0Upgrade linux-image-ibmUpgrade linux-image-virtual-hwe-24.04Upgrade linux-image-7.0.0-1018-nvidiaUpgrade linux-image-virtual-7.0Upgrade linux-image-aws-64kUpgrade linux-image-7.0.0-1013-ibmUpgrade linux-image-oem-26.04Upgrade linux-image-nvidiaUpgrade linux-image-7.0.0-31-realtimeUpgrade linux-image-azure-lts-26.04Upgrade linux-image-ibm-7.0Upgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-nvidia-64k-7.0Upgrade linux-image-7.0.0-31-realtime-64kUpgrade linux-image-nvidia-bos-64k-7.0Upgrade linux-image-7.0.0-2018-nvidia-bos-64kUpgrade linux-image-7.0.0-1011-gcp-64kUpgrade linux-image-oracleUpgrade linux-image-virtualUpgrade linux-image-7.0.0-1011-oracleUpgrade linux-image-oracle-64k-7.0Upgrade linux-image-genericUpgrade linux-image-generic-64k-7.0Upgrade linux-image-oem-26.04bUpgrade linux-image-oracle-7.0Upgrade linux-image-raspi-realtimeUpgrade linux-image-generic-64kUpgrade linux-image-7.0.0-1012-awsUpgrade linux-image-raspiUpgrade linux-image-realtime-hwe-26.04Upgrade linux-image-realtime-64k-hwe-26.04Upgrade linux-image-realtimeUpgrade linux-image-azureUpgrade linux-image-aws-64k-7.0Upgrade linux-image-7.0.0-1014-azureUpgrade linux-image-gcp-64kUpgrade linux-image-oracle-64kUpgrade linux-image-7.0.0-1013-oemUpgrade linux-image-nvidia-bosUpgrade linux-image-realtime-64kUpgrade linux-image-raspi-realtime-7.0Upgrade linux-image-oem-26.04aUpgrade linux-image-realtime-64k-7.0Upgrade linux-image-oem-7.0Upgrade linux-image-nvidia-bos-64kUpgrade linux-image-generic-7.0Upgrade linux-image-azure-7.0Upgrade linux-image-7.0.0-2018-nvidia-bosUpgrade linux-image-aws-7.0Upgrade linux-image-nvidia-64k-hwe-26.04Upgrade linux-image-gcp-64k-7.0Upgrade linux-image-7.0.0-31-generic-64kUpgrade linux-image-gke-7.0Upgrade linux-image-gke-64k-hwe-26.04Upgrade linux-image-awsUpgrade linux-image-gke-64kUpgrade linux-image-7.0.0-1019-raspiUpgrade linux-image-realtime-7.0Upgrade linux-image-nvidia-hwe-26.04Upgrade linux-image-nvidia-7.0Upgrade linux-image-gke-64k-7.0Upgrade linux-image-generic-hwe-26.04Upgrade linux-image-gkeUpgrade linux-image-generic-64k-hwe-26.04Upgrade linux-image-gke-hwe-26.04Upgrade linux-image-generic-hwe-24.04Upgrade linux-image-7.0.0-1018-nvidia-64kUpgrade linux-image-7.0.0-1011-oracle-64kUpgrade linux-image-nvidia-64kUpgrade linux-image-7.0.0-1019-raspi-realtimeUpgrade linux-image-raspi-7.0 | Sep 14, 2026 | Sep 7, 2026 |
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