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Vulnerability · Published Nov 12, 2025 · Assigned by Linux

CVE-2025-40173net/ip6_tunnel: Prevent perpetual tunnel growth

High 7.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.2%top 95.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.158-1DEBIAN-CVE-2025-40173
Debian:13linux6.12.57-1DEBIAN-CVE-2025-40173
Debian:14linux6.17.6-1DEBIAN-CVE-2025-40173
Ubuntu:22.04:LTSlinux5.15.0-170.180UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-40173
Ubuntu:25.10linux6.17.0-14.14UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-aws5.15.0-1100.107UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-aws6.17.0-1007.7UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure5.15.0-1109.118UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-azure6.17.0-1008.8UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1109.118.1UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gcp5.15.0-1100.109UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-gcp6.17.0-1007.7UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1008.8~24.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gke5.15.0-1096.102UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1083.91UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-ibm5.15.0-1094.97UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1095.101UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-kvm5.15.0-1092.97UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-170.180UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1095.96UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1008.8UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1052.52UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1041.41UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1011.11UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oracle5.15.0-1097.103UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-oracle6.17.0-1007.7UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1007.7~24.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-raspi5.15.0-1097.100UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-40173
Ubuntu:25.10linux-raspi6.17.0-1008.8UBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-40173
Ubuntu:25.10linux-realtime6.17.0-1006.7UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-40173
Ubuntu:25.10linux-riscv6.17.0-14.14.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-40173
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-40173
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1064.68UBUNTU-CVE-2025-40173

Affected products (as reported)

VendorProductVersions
Linux Linux 8eb30be0352d09165e94a41fef1c7b994dca0714 – before 566f8d5c8a443f2dd69c5460fdec43ed1c870c658eb30be0352d09165e94a41fef1c7b994dca0714 – before 11f6066af3bfb8149aa16c42c0b0c5ea5b199a948eb30be0352d09165e94a41fef1c7b994dca0714 – before 402b6985e872b4cf394bbbf33b503947a326a6cb8eb30be0352d09165e94a41fef1c7b994dca0714 – before 10fe967efe73c610e526ff7460581610633dee9c8eb30be0352d09165e94a41fef1c7b994dca0714 – before 48294a67863c9cfa367abb66bbf0ef6548ae124f8eb30be0352d09165e94a41fef1c7b994dca0714 – before eeb4345488672584db4f8c20a1ae13a212ce31c48eb30be0352d09165e94a41fef1c7b994dca0714 – before b6eb25d870f1a8ae571fd3da2244b71df547824b8eb30be0352d09165e94a41fef1c7b994dca0714 – before 21f4d45eba0b2dcae5dbc9e5e0ad08735c993f16
Linux Linux 4.7

References