CVE-2025-40183: bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{4,6}
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix metadatadst leak bpfredirectneighv{4,6}
Cilium has a BPF egress gateway feature which forces outgoing K8s Pod traffic to pass through dedicated egress gateways which then SNAT the traffic in order to interact with stable IPs outside the cluster.
The traffic is directed to the gateway via vxlan tunnel in collect md mode. A recent BPF change utilized the bpfredirectneigh() helper to forward packets after the arrival and decap on vxlan, which turned out over time that the kmalloc-256 slab usage in kernel was ever-increasing.
The issue was that vxlan allocates the metadatadst object and attaches it through a fake dst entry to the skb. The latter was never released though given bpfredirectneigh() was merely setting the new dst entry via skbdstset() without dropping an existing one first.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1100.107~20.04.2 - Upgrade
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ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1110.119~20.04.1 - Upgrade
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ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1100.109~20.04.1 - Upgrade
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ubuntu/linux-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-170.180~20.04.3 - Upgrade
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ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1094.97~20.04.1 - Upgrade
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ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1095.101~20.04.1 - Upgrade
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ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-170.180~20.04.1 - Upgrade
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ubuntu/linux-nvidia-tegra-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1052.52~20.04.2 - Upgrade
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ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1097.103~20.04.1 - Upgrade
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ubuntu/linux-riscv-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1095.99~20.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.15.0-170.180 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.15.0-1100.107 - Upgrade
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ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1050.53~22.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.15.0-1109.118 - Upgrade
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ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1051.57~22.04.1 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 5.15.0-1109.118.1 - Upgrade
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ubuntu/linux-azure-fde-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1058.65~22.04.1 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1100.109 - Upgrade
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ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1052.55~22.04.1 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 5.15.0-1096.102 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 5.15.0-1083.91 - Upgrade
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ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-106.106~22.04.1 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.15.0-1094.97 - Upgrade
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ubuntu/linux-ibm-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1049.49~22.04.1 - Upgrade
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ubuntu/linux-intel-iotgto a version that resolves this vulnerability.Fixed in 5.15.0-1095.101 - Upgrade
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ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.15.0-1092.97 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 5.15.0-170.180 - Upgrade
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ubuntu/linux-lowlatency-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-106.106.1~22.04.1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 5.15.0-1095.96 - Upgrade
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ubuntu/linux-nvidia-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1049.52~22.04.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 5.15.0-1052.52 - Upgrade
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ubuntu/linux-nvidia-tegra-igxto a version that resolves this vulnerability.Fixed in 5.15.0-1041.41 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.15.0-1097.103 - Upgrade
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ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1047.48~22.04.1 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 5.15.0-1097.100 - Upgrade
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ubuntu/linux-riscv-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-106.106~22.04.1 - Upgrade
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ubuntu/linux-xilinx-zynqmpto a version that resolves this vulnerability.Fixed in 5.15.0-1064.68 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.15.0-1084.86 - Upgrade
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ubuntu/linux-intel-iot-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1092.94 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1099.108 - Upgrade
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ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1045.46~22.04.1 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1100.107+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1109.118+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-170.180+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1100.109+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-106.106 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1050.53 - Upgrade
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ubuntu/linux-aws-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1007.7~24.04.1 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1051.57 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 6.8.0-1058.65 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1052.55 - Upgrade
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ubuntu/linux-gcp-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1008.8~24.04.1 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1048.53 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1035.38 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1049.49 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-106.106.1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1049.52 - Upgrade
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ubuntu/linux-nvidia-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1008.8 - Upgrade
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ubuntu/linux-nvidia-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-1049.52.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1020.20 - Upgrade
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ubuntu/linux-oem-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1011.11 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1047.48 - Upgrade
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ubuntu/linux-oracle-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1007.7~24.04.1 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.8.0-1050.54 - Upgrade
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ubuntu/linux-xilinxto a version that resolves this vulnerability.Fixed in 6.8.0-1028.29 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1017.21 - Upgrade
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ubuntu/linux-raspi-realtimeto a version that resolves this vulnerability.Fixed in 6.8.0-2040.41 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1045.46 - Upgrade
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ubuntu/linux-realtime-6.17to a version that resolves this vulnerability.Fixed in 6.17.0-1006.7~24.04.1 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1050.53+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1052.58+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-106.106+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1052.55+fips1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.17.0-14.14 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.17.0-1008.8 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.17.0-1007.7 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.17.0-1008.8 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.17.0-1006.7 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 6.17.0-14.14.1
Event History
Frequently Asked Questions
What is the severity of CVE-2025-40183?
CVE-2025-40183 is considered a medium severity vulnerability in the Linux kernel.
How do I fix CVE-2025-40183?
To fix CVE-2025-40183, ensure you update your Linux kernel to the latest patched version that addresses this vulnerability.
Which software is affected by CVE-2025-40183?
CVE-2025-40183 affects the Linux kernel and Cilium software, particularly those utilizing BPF egress gateways.
What does CVE-2025-40183 involve?
CVE-2025-40183 involves a metadata destination leak in the BPF implementation of the Linux kernel.
Are there any known exploits for CVE-2025-40183?
As of now, there are no public exploits known for CVE-2025-40183, but it's important to mitigate the risk by updating.