Linux Kernel up to 6.17.5 virtio_net_hdr_tnl_from_skb initialization

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.17.5. It has been classified as critical. The impacted element is the function virtio_net_hdr_tnl_from_skb. This manipulation causes initialization. This vulnerability is tracked as CVE-2025-40236. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.17.5. Affected by this vulnerability is the function virtio_net_hdr_tnl_from_skb. The manipulation with an unknown input leads to a initialization vulnerability. The CWE definition for the vulnerability is CWE-665. The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: virtio-net: zero unused hash fields When GSO tunnel is negotiated virtio_net_hdr_tnl_from_skb() tries to initialize the tunnel metadata but forget to zero unused rxhash fields. This may leak information to another side. Fixing this by zeroing the unused hash fields.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2025-40236 since 04/16/2025. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/23/2026).

The vulnerability scanner Nessus provides a plugin with the ID 277723 (Linux Distros Unpatched Vulnerability : CVE-2025-40236), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.17.6 eliminates this vulnerability. Applying the patch b625d231c66a6041e98817ffc944bf6e4c45b2e3/b2284768c6b32aa224ca7d0ef0741beb434f03aa 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 (277723) and CERT Bund (WID-SEC-2025-2747). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

Type

Vendor

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

Exploitinginfo

Class: Initialization
CWE: CWE-665
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: 277723
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-40236

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.17.6
Patch: b625d231c66a6041e98817ffc944bf6e4c45b2e3/b2284768c6b32aa224ca7d0ef0741beb434f03aa

Timelineinfo

04/16/2025 CVE reserved
12/04/2025 +232 days Advisory disclosed
12/04/2025 +0 days VulDB entry created
02/23/2026 +81 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-40236 (🔒)
GCVE (CVE): GCVE-0-2025-40236
GCVE (VulDB): GCVE-100-334297
CERT Bund: WID-SEC-2025-2747 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 12/04/2025 17:33
Updated: 02/23/2026 19:18
Changes: 12/04/2025 17:33 (58), 12/09/2025 15:24 (2), 01/05/2026 01:36 (7), 02/23/2026 19:18 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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