Linux Kernel up to 6.17.3 bpf_redirect_neigh allocation of resources

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5.3$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.17.3 and classified as critical. The impacted element is the function bpf_redirect_neigh. This manipulation causes allocation of resources. This vulnerability is handled as CVE-2025-40183. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17.3. It has been declared as critical. Affected by this vulnerability is the function bpf_redirect_neigh. The manipulation with an unknown input leads to a allocation of resources vulnerability. The CWE definition for the vulnerability is CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2025-40183 since 04/16/2025. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 275358 (Linux Distros Unpatched Vulnerability : CVE-2025-40183), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.246, 5.15.195, 6.1.157, 6.6.113, 6.12.54, 6.17.4 or 6.18-rc1 eliminates this vulnerability. Applying the patch 3fba965a9aac0fa3cbd8138436a37af9ab466d79/057764172fcc6ee2ccb6c41351a55a9f054dc8fd/2e67c2037382abb56497bb9d7b7e10be04eb5598/b6bfe44b6dbb14a31d86c475cdc9c7689534fb09/f36a305d30f557306d87c787ddffe094ac5dac89/7404ce888a45eb7da0508b7cbbe6f2e95302eeb8/23f3770e1a53e6c7a553135011f547209e141e72 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (275358) and CERT Bund (WID-SEC-2025-2595). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux

Productinfo

Type

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Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 275358
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40183

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.246/5.15.195/6.1.157/6.6.113/6.12.54/6.17.4/6.18-rc1
Patch: 3fba965a9aac0fa3cbd8138436a37af9ab466d79/057764172fcc6ee2ccb6c41351a55a9f054dc8fd/2e67c2037382abb56497bb9d7b7e10be04eb5598/b6bfe44b6dbb14a31d86c475cdc9c7689534fb09/f36a305d30f557306d87c787ddffe094ac5dac89/7404ce888a45eb7da0508b7cbbe6f2e95302eeb8/23f3770e1a53e6c7a553135011f547209e141e72

Timelineinfo

04/16/2025 CVE reserved
11/13/2025 +211 days Advisory disclosed
11/13/2025 +0 days VulDB entry created
02/07/2026 +86 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40183 (🔒)
GCVE (CVE): GCVE-0-2025-40183
GCVE (VulDB): GCVE-100-332251
CERT Bund: WID-SEC-2025-2595 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 11/13/2025 07:28
Updated: 02/07/2026 19:46
Changes: 11/13/2025 07:28 (58), 11/13/2025 18:57 (7), 11/13/2025 20:02 (2), 12/01/2025 14:10 (1), 12/21/2025 20:23 (1), 02/07/2026 19:46 (1)
Complete: 🔍
Cache ID: 216::103

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