CVE-2025-40183Network attack vector

Service interruption via unreleased metadata destination objects

Published Nov 12, 2025 · Updated Aug 5, 2026

Resource leak in the Linux kernel allows remote attackers to exhaust kernel memory via redirected VXLAN traffic in Cilium gateways. The __bpf_redirect_neigh_v4 and __bpf_redirect_neigh_v6 paths call skb_dst_set() without first dropping VXLAN's existing metadata_dst object from the packet buffer. Reachability requires a Cilium BPF egress gateway using a collect-metadata VXLAN path; sustained traffic continuously increases kmalloc-256 slab use.

CVSS severity7.5
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource leak in the Linux kernel allows remote attackers to exhaust kernel memory via redirected VXLAN traffic in Cilium gateways. The __bpf_redirect_neigh_v4 and __bpf_redirect_neigh_v6 paths call skb_dst_set() without first dropping VXLAN's existing metadata_dst object from the packet buffer. Reachability requires a Cilium BPF egress gateway using a collect-metadata VXLAN path; sustained traffic continuously increases kmalloc-256 slab use.

The record

CVE
CVE-2025-40183
Published
Nov 12, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.10
  2. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <057764172fcc6ee2ccb6c41351a55a9f054dc8fd
  3. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <23f3770e1a53e6c7a553135011f547209e141e72
  4. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <2e67c2037382abb56497bb9d7b7e10be04eb5598
  5. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <3fba965a9aac0fa3cbd8138436a37af9ab466d79
  6. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <7404ce888a45eb7da0508b7cbbe6f2e95302eeb8
  7. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <b6bfe44b6dbb14a31d86c475cdc9c7689534fb09
  8. Affected versionversion=b4ab31414970a7a03a5d55d75083f2c101a30592 <f36a305d30f557306d87c787ddffe094ac5dac89

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <057764172fcc6ee2ccb6c41351a55a9f054dc8fd; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <23f3770e1a53e6c7a553135011f547209e141e72; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <2e67c2037382abb56497bb9d7b7e10be04eb5598; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <3fba965a9aac0fa3cbd8138436a37af9ab466d79; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <7404ce888a45eb7da0508b7cbbe6f2e95302eeb8; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <b6bfe44b6dbb14a31d86c475cdc9c7689534fb09; version=b4ab31414970a7a03a5d55d75083f2c101a30592 <f36a305d30f557306d87c787ddffe094ac5dac89

Published CVSS scores

7.5LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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