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CVE-2025-40183 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix metadata_dst leak __bpf_redirect_neigh_v{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 bpf_redirect_neigh() 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 metadata_dst object and attaches it through a fake dst entry to the skb. The latter was never released though given bpf_redirect_neigh() was merely setting the new dst entry via skb_dst_set() without dropping an existing one first.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/057764172fcc6ee2ccb6c41351a55a9f054dc8fd kernel.org
https://git.kernel.org/stable/c/23f3770e1a53e6c7a553135011f547209e141e72 kernel.org
https://git.kernel.org/stable/c/2e67c2037382abb56497bb9d7b7e10be04eb5598 kernel.org
https://git.kernel.org/stable/c/3fba965a9aac0fa3cbd8138436a37af9ab466d79 kernel.org
https://git.kernel.org/stable/c/7404ce888a45eb7da0508b7cbbe6f2e95302eeb8 kernel.org
https://git.kernel.org/stable/c/b6bfe44b6dbb14a31d86c475cdc9c7689534fb09 kernel.org
https://git.kernel.org/stable/c/f36a305d30f557306d87c787ddffe094ac5dac89 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-40183
NVD Published Date:
11/12/2025
NVD Last Modified:
11/12/2025
Source:
kernel.org